I've got an old Damascus barreled shotgun I've thought about doing this to. I've had it looked over by people who would know and none of them recognized it as having much value. I'd just love to drop a 3 inch magnum into it, tie a VERY long string to the trigger, cock the hammer and get way the hell back out of the way to pull the trigger and see what happened.
As of now the gun is nothing more than a wall hanger. And if for some reason somebody was to break into my home and steal it, that's the very first and only gun I'd want them to take. I'd love it if a criminal were to make a "saw'd off" out of it and try to use it, blow a couple chunks of steel into his cranium while he's out trying to test fire it. That would be nice wouldn't it?