For my custom (which is in the works right now), I was planing to get a web belt and pick up a few various sized ammo pouches from a local military surplus store, as well as a holster or two, then make a few thermal dets to attach on.
JoNich, I couldn't quite tell on your pics over at HVM, but did you happen to get your belt from here?: http://www.imsplus.com/ims1c.html
Because a while ago I was rather interested in the olive drab version.
nevermind that, I'm just going for a regular girth belt. I looked at some hardware stores today and they didn't have what I had in mind. I also looked around google for it and it only had women's chain belts.
depends on whether you want to do a girth or ammo or both... for the ammo any thing goes as long as it doesn't stand out on the custom. the belt should complement the whole costume, not distract from it. for my Mando I'm doing a black girth with a Jango/imperial belt (a Jango ammo/holster with an imperial-ish buckle).
good luck with whatever you choose to do, and post plenty of pics