Hey Bud-
I probably could get an insert for the same as some of these doors, but I want my old brick fireplace. They say they add a lot more warmth and are just better overall. I'd have to agree.
I think tempered glass is stronger, not sure if it acts like safety glass. The door co.'s say they use tempered glass, but either way I'd be sure to have the proper glass made up for me. I was thinking I'd have 2 doors made, 14x26 each with a couple holes put in for the hinges to fasten to. Probably have a few more holes for knobs too....