What about a glass cutter? you know, the little hand held tool you score the glass with and then snap it? I know it takes some practice, and maybe that's way to long of a piece of glass (or thick) to work, but I think if it were possible, then you should have a nice straight line and you could touch up the sharp edge with a dremel. I havn't tried cutting cutting anything thicker than 1/4" this way though...
I dunno... seems safer then running a skill saw through it.
