I got my pistol/gun belt from Amazon.com for about $2.50. They don't come in large sizes, but this fits me. I plan to dye mine.
Chris Pappas Sells holster blanks as well as finished belts. (Or at least he used to...I can't seem to click on anything on the site right now. It's under the "Buy Repicas" section.
(I Know it has nothing to do with gun belts, but you can also order the collar insignia pins from Parade Store, I believe it's the military intelligence with the black painted blue and turned upside-down.)
