Thanks for the replies.

Well for the buttons I think I 'll choose the matrix method (5x7 or more for the future).

About analog I came up with a scheme like this:

The pots will be grouped in 8 rows by 9 or more columns.

One end will be grounded. The other end will be joined for every row together and powered by a PIC pin output.

All wipers in one column will be joined together through a schotky diode and grounded by a 1M resistor, then input to a Analog multiplexer. The output of the multiplexer will be driving the A/D of the PIC.

I know the above idea will lack precision, but this really does not matter a lot if the error is common for all pots.

For the history, the application is a MIDI controller for a music plug-in that has on software many "analog controls" on screen. The idea is not to use the mouse to change the control but a real knob.

Any comments welcome.

Ioannis