The real ones are pricey, except for the one I forgot to bid on on ebay that sold for about $35.00 a few months ago. The typical price when they show up is about 150 - 250 USD, sometimes a bit more on a good day for the seller. They don't show up terribly often.
When my first one died I cobbled up a substitute using a household dimmer. To set it, I connected the dimmer to a track light running a couple of 100 W bulbs, and measured the voltage as I dimmed it till it got to 82 volts. Then I marked that place on the slider.
The fan operates at 120 so you just need a regular switch for it. Ohming out the connector isn't too difficult if you're equipped to do the rest. If I can find my notes I'll post the pinout.
I've since bought a real one off ebay, but I like the slide projector power supply idea. I used my substitute for a year or so, worked fine.