Hi mz,
1. Price is quite variable because a lot depends on who you choose to do the tailoring, where you buy your fabrics, and what fabrics you use. I've lost track of the cost of my costume because it was done bit by bit, with gradual upgrades, additions and ancillaries. I'll list them in the Annex below in small font, just highlight and paste into Notepad to read it all.
Helmet
2. For the helmet, it's not about your body size but the size & shape of your head. If your head is like mine (i.e., too big), you need either a Don Post original, or a fan-made helmet. Don Post helmets are about 95% the size of the movie props and to my knowledge are the only licensed helmets that I can wear. They are fibreglass and bloody heavy. You can try looking in eBay for them. I hear they cost anywhere from USD80 to USD500 depending. The smaller one I have is plastic and much lighter, and clearly re-cast from a Don Post (and thus about 95% smaller than the Don Post). There's an Australian site called Vega Transports but I have no idea about the size:
http://www.vegatransports.com.au/austra ... Guard.html
Other suppliers include Star Fortress and Custom Props (links in the Annex below). If you suspect your head can't even fit the Don Post, let me know, I'll arrange a meeting and you can try it on. If it really doesn't fit, it might profit you to consider a different costume ...
2A. The visor is normally supposed to be sealed onto the helmet hermetically from the outside, but in Singapore's climate, that's a recipe for heatstroke. My solution was to make visors and velcro them on from the inside. This leaves a slight gap which, given how hot it can be inside, is appreciable. The visors were made from red PVC (sold in A4 sheets at this shop at Bras Basah Complex) and you can also add a layer of film (like the kind used for windscreens or windows) to darken it, but be careful what it does to visibility. Nowadays, for high temperates or low light, I prefer to simply go without a visor whilst wearing the balaclava on backwards so all you see through the gap (where the visor is supposed to be) is darkness. That's what I use to speak through: the hole where the visor should be.
2B. There's no space for glasses for me, hence the contact lenses. Again, it depends on the shape & size of (a) your head and (b) your glasses.
2C. For the interior cooling fans, click the link in the Annex. It has photos showing where I placed them. (not that useful, IMHO)
The Detachment Forum
3. Another place to go for advice is the "Sovereign Protectors" Detachment Forum. You'll need to go there anyway to get the CRL standards for joining the 501st, but the place is usually quite "quiet" (as are RGs generally). Try going there and asking around about anything:
http://kaminobase.com/forcepike/forum/index.php
Which Movie Version?
4. In choosing which movie version to follow, my advice is to be practical. But first, the differences. They lie in the arm slits of the cloak, colour and material of boots, material of gloves, and the design of the weapon tip:
AOTC: 2 slits, black leather boots, suede/fabric gloves, "stacked-ring" tip.
ROTS: 2 or 4 slits, red suede boots, leather gloves, "stacked-ring" tip.
ROTJ: 1 slit (on your right side), red suede boots, leather gloves, "serrated edge" tip.
5. The CRLs, in the above order, are available (together with not-always-accurate photos) as follows:
AOTC:
http://kaminobase.com/forcepike/forum/v ... ?f=12&t=72
ROTS:
http://kaminobase.com/forcepike/forum/v ... ?f=13&t=73
ROTJ:
http://kaminobase.com/forcepike/forum/v ... p?f=11&t=3
Please note that the CRLs are not some sort of "law" that you absolutely must fulfill in order to be admitted to the 501st. Admission is decided by the Legion Membership Officer (LMO). He makes the ultimate call on whether your costume is screen-accurate enough, so he might just be more senang/ngeow than one's interpretation of the CRLs. The CRLs are really just guidance provided by the Detachment (i.e., the 501st fellas wearing the costume) based on a number of factors, including their experience, the available visual references (these usually increase very slowly over time) and the input of the LMO who sometimes lurks in the various detachment forums to give comments. The CRLs are also open to anybody who wants guidance on screen accuracy regardless of whether they intend to join the 501st.
5B. The CRLs have something to say about full body armour, look it up. The picture you linked is merely concept art. On its own, it's not accepted for CRL purposes. However, I think the armour underneath is actually acceptable. What is not acceptable is the way the cloth outer cloak has been split. So you can wear the TFU armour beneath the ROTJ cloak, not a problem. But remember the temperature issue, not to mention the weight. I should add that the cloak I'm using has no properly inner lining (it has no inner lining, full stop). Doing that will simply kill me.
Personal Experience
6. Remember my advice on "practical"? I thought I was being practical in choosing AOTC because the boots are damn easy - $35 a pair at Beach Road. But the 2-slit design proved very difficult to manage when trooping - you can get the fabric to drape over the shoulders right when you're putting the cloak on, but once your helmet is on, it's impossible to maintain. Also, near-impossible to get suitable gloves, unless you use ladies' silk opera gloves, which makes it quite hard to grip the weapon if yours is heavy like mine. I also realised that the 4-slit design (seen in deleted scenes/shots from ROTS) is much better in terms of ventilation, which is extremely important. I'm currently using the ROTS design, complete with red suede boots.
Cheers!
PS - Another valuable source of input is Haldir. Go PM her, tell her I asked you to!
ANNEX
Compulsory Items
Helmet - Don Post original, bought from Lord_Tyranno, sent for painting at car workshop using cloak fabric swatch for colour sample.
Visor - scratch built (i.e., made it myself - you'll see this term frequently in the forums).
Cloak, Robe, Sash - fabric bought at Joo Chiat, tailored locally. You need to show the patterns for the local tailors. Cloak fabric is red velvet, the others are a very thin breathable burgundy fabric.
Gloves - bought from http://www.custom-props.com/ (expensive, imperfect, on hindsight too short)
Boots - measured in Bangkok and mailed to Singapore by http://www.liusbootery.com/ (cost me 8,000 Thai Baht). More details at viewtopic.php?t=3976
Weapon - bought from Star Fortress - http://www.starfortressproductions.com/ ... uards.html - not that accurate, but passed the LMO anyway. They have a bad reputation, so it seems I was lucky. The shaft of my weapon is slightly curved and the tip is definitely wrong. It's also VERY HEAVY because it's entirely made from solid machined aluminum. The Sovereign Protectors forum has a guide on making it out of lighter things (like fishing rods).
Other Items (from the most important first)
Large suitcase. Large enough to fit the longest portion of the (disassembled) weapon diagonally across.
Duffel bag that's big enough for the helmet.
Helmet Stand - I use a red IKEA Fniss wastebasket (which you can see in the avatar). Turned upside down, it's a cheap helmet stand. It can also protect the top part of the helmet when you're transporting it (I still don't know how best to protect the lower flared shoulders other than using towel cloth).
Disposable contact lenses.
Long-sleeved Skins compression top (for wicking sweat) from Isetan Orchard (golfing section).
Black Nomex Balaclava from Sheares Tech - http://www.sheares.com/index.php - but this is not a commonly-stocked product. CALL THEM FIRST. These days I often remove the visor and wear the balaclava backwards (which is actually inappropriate). This method absorbs sweat that will otherwise run down the helmet and drip visibly onto the cloak. Without the visor, it's also cooler, doesn't fog up, and you (probably) see better.
Black sports slacks.
Black No. 4 socks from Beach Road.
DH-17 blaster (off eBay) - this is the blaster used by Rebels, Royal Guards and the Imperial Navy, with minor detailing differences from the Rebel version. You'll have to make your own repairs, paint job and weathering first. Buying off eBay means you risk a costly bidding war.
Red leather holster - made at a shop at Orchard Plaza, can't remember the name but can bring you there. I also made a burgundy leather belt to replace the sash, in order to hold the weight of the blaster.
Helmet cooling system of computer fans, wiring and battery system - parts available at Sim Lim Tower, not very effective, used it for Chingay. See viewtopic.php?t=3841
Red leather iPhone case (just in case).
Voice amplifier with microphone - available at Sim Lim Square (the precise name escapes me but it's somewhere in these forums I believe). These days I just shout through the empty visor slot. Do not shout if you are wearing a visor - your voice with deafen you.