If you are still looking for a shop, shoot me a PM. I have a friend that runs a shop and I know he has a brand new "state of the art" flush machine. If you do all your routine flushes with this machine, the company will warranty your drivetrain parts. Kinda makes you a believer.
That said, I would also advise against using one of these pressurized machines to flush certain systems. For instance, a tranny with gunk as mentioned above... a simple DIY drain and refill will not disturb the buildup, where the flush may break it loose and clog filters/hoses/parts/etc.
If the vehicle is new, its the best thing around.. high miles you should really think twice about it.