VOL+: volume + tone control; or “volt”, since it also has a clean boost. The idea with this pedal is to move the guitar’s built-in controls outboard, so that players can control volume and tone with their feet while picking (hard even on a Strat; nearly impossible on most guitars).
For the T/V and Bypass switches, I really like these switches with integrated LED rings!
Volume pedal with a treadle as usual, but also with a rotary switch to select between various treble bleed capacitors (and off/no treble bleed).
Volume pedal with switch for volume vs. tone; rotary switch for which capacitor (also functions as treble bleed capacitor, if that can work). (Maybe different banks of capacitors are selected the pedal is in Volume vs. Tone mode, if that is necessary.)
General idea: treadle pedals of any kind, with several controls (e.g. Volume/Drive/Tone, Level/Rate/Depth, et c.), and a switch to select which parameter the pedal controls. (The other parameters would continue to be controlled by their knobs.) Then people could change a parameter in real time with their foot. (I often want to do this with distortion and phaser, for example.)
The switch could be a second footswitch, and multiple taps might allow the player to cycle through which parameter is controlled by the treadle.
Maybe what we need is a treadle pedal mechanism and enclosure as easy to get as the usual 1590B/et c., and then people can come up with whatever ideas.
You can get a Crybaby-like kit, but that isn’t quite what I’m thinking. I’m imagining a smaller treadle/shorter foot, with something like a 1590B or similar on the side.