For all things spandex
http://www.SpandexWorld.comIf you want to get crazy with the camo or make real functional raingear or other outdoorsy stuff
http://www.rockywoods.comhttp://www.questoutfitters.com for more outdoor stuff and sometimes they have interesting remnants.
The outdoor folks seem like a crazy idea for scale sewing, but they cater to ultralightweight backpackers, so some of their material is very lightweight.
And
http://www.denverfabrics.com for some really nice silks and wools. Somewhere in a box in a closet (story of my life) I've a scrap of
tangerine silk twill that would make the BEST elegant formal dress.