I really like the Retropie project and I’m using it regularly on my Raspberry. Problem is that the Raspberry is not a very powerful device and lots of games are running to slow.
All the RetroPie script does is install, compile, and configure open source emulators. You should be able to do this yourself on any Linux device.
If your ARM device will run Raspbian (like the Cubieboard, for example) the RetroPie script may even work out of the box. I’ve been considering picking up a Cubieboard for just that reason.
I would be interested in that as well. However, I do not have the resources and time for that so that everyone is invited to contribute here. The script uses some RaspberryPi specific emulator ports, which would have to be modified accordingly (I guess).