I was able to dig up 2 pics from the THX guy I saw at Dragon*Con. Not sure what year and I don't know who it is other than the pictures have the name Randy in it. It's a cool ass costume, though.
I recall this discussion coming up about a year or two ago. I too am interested in doing this costume. At the time, I think it was mentioned that the helmet and boots were real CHP issue.
Me and friend decided to dress up as a police droid and citizen at 2009's Scandinavian Sci-Fi, Game and Film Convention in Stockholm. I edited together a 2 videos of the event showing us off in the costumes. Oh, and if you get bored watching the random footage in the beginning of the video you can fast forward to 03:15 in part 1 when we switch into costumes.
I had the easy part of just being a citizen and yeah yeah - I know - shaving of the facial-hair should have been mandatory but then again I have some real issues with getting rid of that and my friend wasn't ready to shave his head so I just took it as far as I felt like. Either way the chrome mask done by my friend felt like it worked out quite well (apart from being real warm that is). He essentially used a simple cast of his face and applied a lot of glossy coating over some kind of metallic looking paintwork... oh, and simple pinholes done by needles for something to see through.
My citizen suit is far from perfect but we didn't feel like spending a fortune so went for fun rather than dead on accuracy. :rolleyes
LOL. Yeah, to be honest Ironside was close to the only one there who actually recognized us as something from THX 1138 - everyone else just assumed my friend to be the T-1000 in his motorcycle cop uniform (carrying a long stick around for some reason)... and I guess they just saw me as a poorly dressed punk who happened to have stepped on his toes or something.
I'm still bummed that I managed to hit a nerve by not asking if I could film him (I always ask but on this occasion I was just caught of guard as he noticed us in line and struck up a conversation by pointing out that he liked our costumes and seeing as I was already filming I just forgot to ask as we continued talking once we came up to the table).
Glad he turned around for the better in part 2 though.