That would be a popular product. You could potentially make your own if there is room enough and the pedal chassis is robust enough. Use a mini switch if necessary.
I want to be able to switch my expression pedal between, for example, controlling the wah, to controlling the volume. The simplest approach is to have an expression pedal with two jacks, both of which plug into the QC’s expression jacks (EXP 1 & EXP 2). One jack is for the pedal sweep and the other uses the toe-switch to control the bypass state of (in this example) the wah and volume blocks. No doubt already common knowledge to many players here.
Think I am going to try and mod my M-Audio expr…