Well, I searched and searched and the best I could find was that there is a group that likes tinted glass, and of that, only a few have actually reported what level of tint they are using.
With that little bit of information, I decided to just buy glass today and see what happens, so I called a couple of glass companies and got a 26" x 25.75" piece of Graylite #14 (pretty dark stuff) since I saw it referenced here on several occations. It ran me $34 for it cut with the ended sanded and polished so that I don't cut my hands on it like I did with my old cabinet's 1/8" thick clear glass. It is NOT tempered, but neither was my last cabinet, and it never broke. The old one did chip in one spot, but I was holding it up mainly on 2 screws only. This time around I am going more professional and using a full 26" wide bracket to hold it up, so it shouldn't chip. As for safety, my 1/8" clear stuff didn't break after being moved twice, and after over 7 years of use, this stuff is 1/4" thick, so it should be more durable as well. If I wanted tempered, it would have been about 3 weeks to get it in, and I would have ended up paying over $90 (best price in town) for it. If I would have stopped by the glass shop this morning instead of over lunch, I would have been able to pick it up yet today, but I will end up with it tomorrow (Tuesday). I will take it home and get it installed tomorrow night and try out the DC Light Guns myself and report back to the forums with my findings.