For the VRM, it looks as though the VEX Canada warehouse (click the American flag near the top and select the Canadian flag to see the Canadian warehouse) and Studica.ca have them in stock currently. I’m not sure if they offer shipping to the US, but could be worth a look into.
The RPM from REV is great for powering the radio. Had an amazing experience with it this past season. That being said, there’s definitely uses for the VRM where the RPM will not work. The VRM will provide regulated power of varying voltages (12v and 5v) to various electronics/custom circuits onboard the robot. The RPM is specifically for powering POE enabled devices like the robot radio with a regulated 18v.
This is correct, and I had put that out of my mind since we only ever ran one VRM and dedicated it to powering the radio. Good catch!
Though if you’re trying to convert battery voltage to a certain voltage for a custom circuit, the simpler answer in current times is probably to source your own voltage converter and integrate it into your custom circuit.