Hi Shum, i working exactly on such a project. :D I bought an old CRUMAR Heaven organ which has a 5 octave and a 4 octave keyboard, 26 drawbars and a lot of buttons. I took the original PCB's out and developed my own electronics to midify the keyboards including velocity and aftertouch. I know that velocity and aftertouch is not needed for an organ but so i can use the keyboard also for other applications. To modify the raw midi data i receive from my electronic i use a PIC with MIOS. I wrote a piece of software to control the midi channel,octave shift, transpose and velocity key curve. The drawbars and the buttons i midified with MIDIBOX64. The project is nearly finished now. There is only some mechanical work to do and some improvements in my software. If you are interested i can come up with some more details. Have a nice day Beethoven