The board looks great, except it looks like it's missing a rather large heat-sink. Adding a heatsink looks difficult.
I LOVE the voltage range, it's perfect. Most serious servo motors want 80-90VDC for their rated performance specs. I'm so sick and tired of drives and amps which seem aimed at the combat robot/wheelchair style builder who is limited to 24VDC.
I note you call it power supply, though you may actually mean servo drive, which uses a high voltage/high current power supply to power a high-torque motor or gearmotor combination.
FYI, my motors are the odd duck ServoDisc motors, so my power supply is customized for them. My development is still underway, the first phase will be limited to about 31VDC, and later expanded to approx 80VDC.
Since I've purchased a lower voltage drive for 3 channels, I've been thinking about using it's output to modulate an external circuit running at 80VDC (MOSFET switching of ground). I worry about presenting enough of a load to the amp for it to remain happy.