You might want to just try purchasing some fingerless weight-lifting or biking gloves and modifying them. My friend used some super cheap knee pads he got from Home Depot for his Vash costume, and even with out touching them up they looked pretty good. If you did actually put some time into modifying them, I don't see how that wouldn't work. And it'd be way cheaper too--ever seen how much the 'official' Trigun Vash sunglasses go for? WAAAAAAAAAAAAAAAAAAAAY too much, aheh. ^_^ Hope that helps.
I could make the kneepads and elbowpad for you ^_^. Gloves.... get a pair of opera-length black gloves that fit you (opera length 'cause one needs to come up over your elbow). You could make all the little belts and stuff on them out of black ribbon or webbing (black elastic, even). Add little metal studs and maybe a few little buckles, and you're all set. Tack the little pieces on to the seam on the gloves with some hand stitching so they stay in place. Ta-da.
Contact me via PM or AIM if you want me to make the pads for you ^_^.
Well I have the glasses, ( got the offical ones...) and Looking for offical gloves just because I collect too hehe.... Any way I will try the opera that way it will be a double layer ( I have a full body suit already) any tips for studs, rings ( I made some in metal shop last year but by end of con. I had about 3 left,) and the two funky straps on top of the glove?