Hmmmm... I guess I didn't realize that you were pouring this work into this Ribbon Controller, @sebber, and you asked about this elsewhere (perhaps via support)... in 1.6.1 we have a Control Type (or Subtype, some inconsistency there) called Transpose for a supercontrol. That would allow you to do with this 126 less buttons. SORRY for the late notice on this one. I'm not sure if 1.6.1 wasn't out yet, or if I just didn't realize what you were trying to do.
Anyway, glad to have this layout, but I guess we'll need to have a response layout using transpose, too.
Thanks!