The best way to control this sort of thing is digitally. ie stick all your effects in a properly shielded, earthed and powered box and then run a digital communications link from your foot pedal to your box of tricks. This will cut out hum pickup, a big fat cable, lots of switches etc.
You would have to do a full on design and have to write some software as well to make it work properly.
This is bordering on what I do for a living. (Factory plant control software) so I don't think I would like to get involved in this, I build guitars to give myself a break from that sort of thing. (I might have to start charging professional fees to motivate myself. HaHa)
But seriously, if I've learned one thing in engineering it is: KEEP IT SIMPLE also known as the KISS principle. Get a few simple effects working first before trying a bigbang type project.
Keith