Hello David

> Assuming that each board is set-up the same is there any reason why 4
> boards can not be wired to single set of controls and sockets

Only the VCF Cutoff, and the VCO tuning are direct voltage controlled
parameters. All parameters of envelope, LFO, and all modulation-amounts,
levels mixing potentiometers, switches are direct parts in the circuitry
and cannot be controlled by a CV (which is essential for a single
controlset).

You might use fourfolded potentiometers, but these are around $20 each...

Or you would build a huge pcb with additional VCAs and CV Switches.

Florian