I have a schematic that will do phase reversal, on/off and series/parallel in two switches per pickup. It's on a shredder style Steinberger so it also has an aditional switch for coiltapping (North/Hum/South)
If anyone is actually interested, it amounts to the freedom of any combination of series and parallel with phase reversal and you dont need all pickups on. There are catches like any other system, but without coil tap, you do all this in 6 switches.
3 are On/On
3 are On/On/On
I also modded the cuircuit for the black ice/strawberry distortion to use a on/on/on switch to give you the option of one diode/both/off.
If anyone wants diagrams, let me know and I'll draw some up.
God bless guys,
PP