My ongoing search for an appropriately large and still cheap chest freezer or fridge has been fruitless, so I'm kicking around an idea... let me know any concerns.
Start with a cheap dorm fridge (little ones are very cheap)
Build an insulated enclosure, large enough for one fermentor (I think I'll only need one at a time).
Run two ducts from the fridge to the box. Maybe through the front door...
Install a fan in or near one of the ducts
Run fridge full time, maybe with jugs of water for thermal mass, and hook up fan to temp controller.
In theory, I should be able to chill, but I don't know if I can keep up with 5 fermenting gallons of beer (especially if I want to get down to lager temps). I'm no engineer, and kind of a hack, so let me know if I'm off my trolley with this...