Didn't found anything about so think it doesn't exist yet....
As far as I read in the Midi Documentation u can program an FootController to change nearly everything, also things I'd never thought anyone wants to change with a foot controller.
BUT
Is it right that u can't switch Rigs up and down? (With MIDI, I know you can do it with switches)
It's a great feature if you want to test a lot of rigs.