Bought one in Wallingford a couple of weeks ago. It was labeled "KWM-2 Power Supply" and has all the usual voltages for that class of transceiver. I've asked about it over on the 'zed and as of now nobody's replied about it. I was sure at least one of the Collins fans over there would have.
It's very compact and extremely well-built. I'll take some pictures over the weekend. So far I've only managed to get the top cover off, and it doesn't come off very far 'cuz it's wired into the guts. And while the side label says it has variable bias, I've so far not found anything that looks like a bias adjustment control.
It looks built to almost military standards. The wires from the guts to the connector are very well laced, so about now I'm guessing that it was probably priced like it was gold-plated, hence the "KWM-2 Power Supply" that's written on the side. Maybe that's why they're so rare? I think I remember seeing them once or twice in QST ads...I'll have to look through some of my handbooks to see if I can find anything. So far, google-fu has failed me. I see references to Topaz supplies, but nothing near what this is. The fun of the stuff you can find at hamfests!
And isn't it ironic? One week I get that and that'll get the TR-3 going in the car for mobile AM...the very next week I get the Multi-Elmac to get plate-modulated-AM in the car. Yikes!