There's bound to be a decent Baaaaass player in that there field
Bluetooth bar is a great idea, but difficult to make and tricky to use I would imagine. You would have to have at least one switch on the bar, I could see it being pressed accidentally, probably need more than one switch to make it worthwhile. Although the receiver could be programmed to be multifunction from a single keypress on the bar, so I suppose you could have patches or a sequence of patches set up to correspond to a set list or whatever.
In any case the circuitry would need to be housed within the bar and would need decent battery power which would need to be either charged or a change of batteries required. If only we could use a thought control device, which are being developed with some limited degree of success but could be a few lifetimes away.
On the pedal switch idea, it occurred to me that if you used a stereo output jack, the switch output could be connected out via the 2nd ring and a breakout cable used to split the pup out from the switch output, so no need to baaaaastardise the guitar.