Rikki, you are such a generous person. You could be letting Jos off the hook for creating a few translation tables within or for OMB. But who knows it may be Rikki who develops the translation tables from Yamaha to GM. I would take that too!!!

GNMidi is the 'Swiss Army' knife for midi files. It has many features for changing, fixing, etc. midi files including transposing designated notes per channel. You can take a look at the following site:
http://www.gnmidi.com/