Hi.
Cool idea.
You may have seen the Tom Hanks movie 'big' which features Hanks playing a giant light-up piano with his feet; thanks to google images heres a picture:
This getup is required by everyone doing the stage show version of the film, and many of them use a
MidiTron interface, which converts contact presses to MIDI, which is then fed to a MIDI sound module, to make it sound right, and to a lighting desk that can accommodate MIDI messages as control elements. This is much the same as your proposal of a PIC controller, 'cos thats actually what the MidiTron is, and it's not really the PIC you're paying for, but for the firmware and programming software, which just works. Unless your time is genuinely free, then it doesn't take much of an hourly rate before you could have bought the off the shelf product.
There are many lighting control products that can work with MIDI, the products I am somewhat familiar with that do this include BlueLite X1, ShowMagic, and my chosen platform, PCStage. None of these are free, however. Many PC based control tools, and many proper consoles support MIDI. Be warned however, Zero88 frogs don't!
