Alright, so I've got an idea rolling around my head, but I'm wondering if a certain aspect is possible:
Is it possible to have 2 switches, one latching, the other momentary, where the momentary basically reverses the state of the latched switch?
For example, if the latched switch was set to off, pushing the momentary switch would turn on the circuit, and if the latched switch was on, pushing the momentary switch would turn off the circuit. Basically, adding a momentary switch to an existing pedal to let you kick on/off an effect for short bursts by holding the switch, depending on what state the pedal's already in.
I think it depends on whether the pedal uses a mechanical switch or FET switching on the circuit board. With a mechanical switch, it shouldn't be a problem to wire up a momentary switch in parallel with the main switch that would do the same thing but just not latch.
This is where digital multi-effects are more flexible than individual pedals.