MIDI programmer

[boldman at interplanet.it]

Hi everybody,
is there any DIY project for a midi device which assign a slider or a pot to
any of the 128 possible midi controlled parameter.
In other words it should be possible to build a generic midi
controller/programmer to be used in connection to any synth which accept
external midi message as midi controls.
Something like the enormous DX7 controller, or the specific controllers for
many roland synths (from the mks80 to the d550).
Probably too slow for live performance, but useful enough for programming
at home.
HHHHmmmmm, it should work in both modes: handshaking, one way only.

Silly idea?
ciao
riccardo