I work at a sign company, we do sign faces out of plexiglass and Lexan quite often, with alot of drop sometimes. we have a machine called a shop bot, which is guided by computer and cuts with a bit the desired shape out and leaves a clean edge. You get your dimensions and plot out the shape on a program, save it to a disk and upload it to the machine and it cuts it. It comes in clear, and a transluscent white, and in 1/8 or 3/16 inch thicknesses, that's what we use and probably 3/16 would be your best as 1/8 is to flexible. Yes a jigsaw does tend to melt the edges but if you use a correct blade for cutting plastics, it can be minimal and you can always just sand the edges to get them smooth. Scratchin lexan is as easy as taking a breath, it comes with a protective film on either side but once you take it off, any little thing can put a scratch in it and I doubt there is anyway around it, and as for breaking, Lexan is pretty indestructable and supposedly bullet proof?? but dont take my word on the bullet proof thing!
I hit a old McDonalds face made out of Lexan with a sledge a bunch of times before it finally cracked, so flying shrapnel should be of no concern