Depends on what exactly you are trying to make. I've made a number of jigs out of 1/16" (0.0625") brass stock over the years. It is pretty tough stuff, especially once it has become work hardened from bending and hammering.
I can't help you with sources though, all my former sources were in Bradenton, FL (and I'm not sure they carried 1/8") -- WoodWrangler's neck of the woods these days IIRC.
Best of luck. If you, or others, find, or know of, a good mail order source I'd love to hear about it as well.