Ever cracked that thing open and seen what's on the inside?
Seems to me it'd be pretty easy to build such a thing, probably nothing more than some R/C circuits, or maybe some counters and a DAC in there. Even looks like it comes in a standard-sized project box.
(Now you've got me thinking about grabbing a small microcontroller like an Arduino and programming it to emulate such a gadget. The only heavy part of the project would be a power transformer to step wall voltage down to 50VAC, but it'd still be a lot easier for testing purposes than the present requirement of "drag the monitor near a working machine, or drag a working machine near the test bench...")