I've heard of someone using macaroni boxes covered with some black material.

For mine I used black funky foam and ceral boxs, they look pretty nifty

http://cgi.ebay.com/ROMANIAN-MAGAZINE-RIFLE-MAG-AMMO-POUCH-LEATHER-MILITARY-/200514258990?pt=LH_DefaultDomain_0&hash=item2eaf94c82e

^These. Swoz used them for his soldier. Some minor modifications and some black spray paint, and they're good to go.

I've used macaroni boxes, cloth, spray on glue, and velcro. They hold up amazingly well for fabric covered cardboard as long as you don't sit on them. All I had to add was some gray paint to the velcro to make it look like it was actually a button.