Thanks for posting that link Al... good info.
Skyko makes that pixie card that I think you were referring to btw. The one that converts 5v digital to 10vdc analog. However, people are warning that they are not responding to inquiries at the moment.
I wonder if the digital-to-analog (0-10v optional) feature that the G-Rex controllers offer means that it is capable of driving a 10vdc analog amp like the BA series? I have wondered about this after reading the G-Rex description PDF and seeing this option.