I keep looking at the $249 Empress Parametric EQ as they are great for sculpting the sound of your guitar, or the BYOC kit for half that price. However trying to fit a good portion of that circuitry into a strat would be quite a challenge.
Is there a particular reason that you want it installed onboard? I imagine that there are custom guitar makers who would build such a guitar for $2K-$3K.
If you wanted to build something yourself you might start with the BYOC kit and then replace the pots you did not need with fixed resistors or trimpots (for internal adjustments) and then etch your own custom PCB.
As for powering such a device I would use an external battery box connected to the guitar via a stereo cable since the batteries would need to be changed quite often.
Dual concentric pots for guitars are usually available in just a few resistances like 250K. For other values you might check electronic suppliers like Mouser. Be sure to get all of the specs so that you can find the appropriate sized knobs.
Or you could wait a few years for some company to come out with a digital pedal controlled by bluetooth from an LCD screen embedded in a strat pickguard that could do all of that and so much more... it could happen.
Steve A. (one of the moderators)
P.S. I can move this thread to the Guitar Effects subforum if you want as those guys know a lot more about electronics than guitar techs.