The Artillery Luger is Chuck W.'s grail gun. They are available, being semi-automatic and old enough to be considered C&R, and occasionally come up in auctions.
He doesn't want just the pistol, though, he's holding out for the full set-up, snail mag, shoulder stock, holster and all. Here's a nice example that sold in 2010 for $6000.
This is another one I'd never heard of until I started looking up everyone's grail guns. I knew what a Luger was, but didn't know enough about variations and the history. I'm pretty sure that the one pictured is what Chuck W. has in mind, but if not, I hope he will leave us a comment, a correction, and perhaps a link or two to more information about this piece of history.