Hey,
The hardware for v3 is ready for mast with diameter 32mm. In the master branch, we are working in the rotator with mast diameter 40mm that is almost ready. In the X/Y configuration you need additional parts to support and connect each separate axis. So if you start to build v3 you have more choices than v2.
As @elkos said you can use the same electronics for stepper motors. Also you can use the new satnogs controller that you can control stepper motors or DC motors. In order to control DC motor we use magnetic encoder with 12 bit resolution. The firmware for DC motors isn’t stable yet. The new pcb’s isn’t available in OSH Park but we do in the next days. So, i recommend you to build new satnogs controller in order to have more choices.