As far as I know, My Little Pump it Up is the only fan-made project dedicated to ponifying StepMania 5 - which, to be honest, sounds pretty cool. Maybe this could be the next convention gaming staple.
The team is creating the interface more or less from scratch, but they need money to purchase a machine in order to show off the beta at BronyMexiCON. Head over to their site to check out the project or donate!