side-note: do you know where I can get my greedy mitts on sheet polycarb/lexan of that type, 1/8" thick and in normal industrial lengths/widths?
If I knew the exact chemical name for the stuff, or a particular rating, that'd be a start.
It comes under many trade names and formulations, but you should just look at any big glass supplier in the yellow pages. They'll answer to Lexan or polycarbonate plastic window material. All thicknesses, clear, coated, tinted, what ever you need. No problem, standard stuff. 1/8" thick is not bullet proof, if that's what you want. One inch thick and up for pistol bullets.
Lexan is commonly used by drag racers, so I would begin with the aftermarket drag people. In fact, you might hook up with a local racer for scraps, possibly via some of the racing forums on the net.
http://www.sheffieldplastics.com
I work here.