The new REI shop in Robinson Township, PA (just outside of Pittsburgh) has a large ultrasonic cleaner in it's bike repair shop and the mechanic there seemed quite enthusiastic about it when I last talked to him. You might give them a call and get his take first hand. He should be able to tell you the make, model and cost of the unit they have as well as what cleaning fluid they use.
Here is the store location and phone number:
Settlers Ridge REI Store
600 Settlers Ridge Center Drive
Pittsburgh, PA 15205
(412) 747-1180