I have a single axis system with a CTI 6900 galvo; this thing is huge and can swing a huge mirror - it's rated for a 50mm aperture! Apart from the speed (lack of), of course, the galvo has impressive specifications. The amp contains a 6500 galvo driver board and 2 huge linear PSUs rated at 20V / 10A each;drive to the galvo is via a pair of power devices on a separate fan-cooled heatsink. As well as the driver, there's also a 16 bit DAC on a separate board, along with 3 x LS244 octal buffers, so this unit is parallel digital data in; it should be easily modified to bypass the DAC should you wish.
The amp is enclosed in a 3U 19" case.
I guess this is rather specialised, but if you need one of these systems, you'll appreciate that they don't turn up very often.
Open to offers on price at the moment, bear in mind that this was CTI's flagship scanner not so long ago!