I'm curious. I use a 2:1 transformer, bridge rectifier and
caps to power 80V AMC drives. This comes out about
4V high but hasn't seemed to cause trouble. For a cheap
voltage drop could you just run the DC out through a couple
more diodes on a bridge rectifier?

Yup. Each silicon diode gives 0.6V to 0.7V drop. Make sure the diode's
current rating is sufficient.