Beer Dr.,
When I was at the MM dispense class, one of the other participants was the owner of the Capital City Ale House in Richmond VA. Their contact info is
Capital Ale House - Reviews - Beer Advocate
They said it was a good marketing gimmick, but a real pain in the butt to maintain and it didn't really (read: "at all") keep the glass cold. Also, you have to completely empty the "trough" every night and start with fresh water the next morning since it gets dirty and gummy. I recall he had to use distilled water (or something special) so that the ice would be clear; tap water freezes too cloudy.
I got the impression that if they had to do it again, they wouldn't. I think they were one of the first places to get one, so perhaps the technology has improved. I think his name is Chris.
Cheers.