I too have been sorta keeping an eye out for one. They pop up on occasion on ebay, but that's the only place I know. I've thought about making one myself, but for the cost that they sell for when they do pop up, it doesn't seem worth the effort. Plus, while they're completely different... the main problems that I'd use it for can be diagnosed with a thermal camera. I do love having tools on hand though, so if I ever do finally come across a good deal on one, I'll pick it up.
I don't think that's what he's looking for... I believe the OP is (and I am) referring to the HP 547A. It's been obsolete for quite a while, and given that they don't pop up that often, I'm guessing that they weren't that popular.