I've run these pictures past a few people, and no one has been
able to tell me what this thing is.

It is modified, probably to use on a ham band. But I would
like to know what it was originally. It looks like it has three
stages of frequency multiplication... so maybe it was VHF or something?

front:
http://www.yipyap.com/radio_stuff/xmitter1.jpg

front with doors open which give access to tube bases, fuses, etc:
http://www.yipyap.com/radio_stuff/xmitter3.jpg

Dimensions are roughly 4ft high, 3 ft wide and 18 inches deep.
(I've got it out back if someone wants me to go look for something.)

Any guesses?

Chris