Have you considered finding the required voltage, and wiring a setup yourself? I'd imagine either 1 or 2 AAAs would work just fine, coupled with the proper resistors. I've done this with a number of cameras, including rather delicate SLRs, to test them out when I don't have the battery. Get some alligator clamp leads and a couple of 1 and 2 battery housings at your local Fry's, RadioShack, etc. Also, remember your resistors, and a plug board. You just wire the boxes into the plug board, and use the resistors as leads to one side of the alligator clips.
Voltage = Impedance (Current) * Resistance, so Resistance = Voltage/Impedance (Current)
Remember, if you can't get the rated current for the camera, you can use protection diodes to just cut the voltage straight. Typically 2 x 1.5v batteries ---> protection diode -.5v = 2.5v available. Buy a few diodes so you can use them in series, as needed. Then just hook up the alligator clips inside the camera terminals and watch your machine come alive. A little gaffer's tape and the whole getup becomes portable.