This was what was originally there, Scott. It's got a rather distinctive base, and I was lucky enough to recognize it while driving down the street at about 35 mph. If I get real crazy, I might attempt to reproduce the cabinetry, but for now, I just want to put up a platform so the machine is usable. It wouldn't hurt my feelings to find an original cabinet, though.
The machine was cheaper than the treadle base, sort of. Maybe not -- the Mochi table top is probably worth more than I paid, so maybe the treadle and base was free...
The Davis machine, according to what my wife found wasn't all that uncommon, but sure wasn't Singer.
Thanks a lot for the parts dealer info! My wife will appreciate that!