Coil split two pickups with one switch?

Do you want to be able to move the switch and have both pups go from HB to SC at the same time?

If so use a 4PDT switch. It's basically two DPDT's as used in std coilsplitting, but all in one housing and with 12 terminals instead of 6.

4PDT



DPDT



Imagine gluing two DPDT's together and wire up as per diagrams on Bart, SD, DM sites. Looking at the above 4PDT, wire neck to 2 rows of 3 terminals, and bridge to the other 2 rows.

Note DPDT is photographed laying on it's side (90*) relative to the 4PDT photo.

As for where to get one, I'm not in the US, so google should bring up something.

 

http://www.seymourduncan.com/support/wiring-diagrams/schematics.php?schematic=2h_1v_1t_3w_1pp
This is the standard seymour duncan wiring to split both humbuckers with a push-pull vol (or tone) pot. Just substitute a dpdt on-on mini switch with the 6 lugs instead of the push-pull if you want a separate switch. You can get the switches from ebay or most guitar parts suppliers on the internet.

 

You should be able to do it with any normal DPDT switch. All you are doing it shorting one coil from each pickup to ground.