I have heard that there are a lot of limitations with what you can do with a MFC10 and a PSR2000/2100. You can program any midi signal or sysex signal, but there are a lot of footswitch functions that you can setup with the PSR9000/Tyros that you can't setup with the PSR2000, 2100, or 3000.
I discovered, for example, that the FILL SELF function is created from a note on/off message when the MFC10 is used with the Tyros. This message does absolutely nothing when fed to the PSR3000.
Also, there is no such thing as an MFC-7, to my knowledge. A Google search confirms this.
Good luck,
Beakybird
[This message has been edited by Beakybird (edited 11-13-2004).]