I've had the idea to replace the volume pot in my Telecaster with a push/pull, which could switch my pickup wiring from parallel to series when I have both p'ups selected. For starters, is this type of mod even available? And how difficult would it be to get this done, would it be worth it?
Fender American Special Telecaster w/ Bigsby
Fender MIM Jaguar
Digitech Whammy-->Korg Pitchblack Poly-->Dunlop Cry Baby-->Danelectro Pastrami Overdrive-->EHX Big Muff Pi-->Joyo Digital Delay
Fender Hot Rod Deluxe III Red October Edition
It might sound too thin. Me personally I wouldnt mess with it, but if you threw in a 5 selector switch you could have them in series and parallel and out of phase. But honestly I think teles are awesome the way they are.
It's a really easy mod. Fattens up the sound a lot, like a humbucker. When you pull the switch, it bypasses the selector, so you can easily go from neck to both in series, etc.

Here's a diagram:

If you want I can give you a diagram to integrate a phase switch as well.