I would be curious to see that list too, as I'm sure it is very short.
Superbcert uses it for their stones. Diamondbrokersofflorida have it, but don't have results posted on the net. You need to call and make a request.
It seems to me that there are other vendors selling their own brands (like the LEO diamond and the Zale diamond) who use it as an advertising tool.
I think Rockdoc is the only appraiser with one, but there may be others.
The word also is that GemEx is pulling the machine from vendors and leasing them to cutters only. Maybe someone can comment on when that was supposed to happen.