no, however, I remember reading something about accessing a portion of the iPad's screen and using a bluetooth pedal to activate that pixel area...
I am sorry but I do not have any idea where I saw it.
However, here is what I would do if I were you, if it is absolutely necessary.
Don't use the delay in the DL mixer,
instead, use an aux send from the mixer and connect it to a delay pedal.
This will allow you to send any channels to it, and it certainly would have a tap tempo feature as well as a bypass,
BUT.....if you find something, make sure that when you hit "bypass" it does not pass the audio input through to the output, because that will add to your mic's volume, not good.
Even if you found a delay pedal that does not have a MUTE feature, you could always use a separate MUTE pedal to mute the output of the delay pedal.
