I have one of these Morley Split-Mix units, that acts essentially like a dual-channel buffer/booster/mute when you run both 2 inputs and 2 outputs (A input goes to Output 1, B to Output 2): Morley Twin Mix Dual Channel Mixer/Combiner Pedal
Not a perfect solution for you because its not a one-footswitch solution, but you could definitely hit both switches simultaneously. Use something else to split your signal (like the Boss), then put something like this at the end of your FX chains and before the DIs and it could work. Bonus is you get a volume control for each channel right before it hits the board.
I see its also been discontinued like the Empress solution I posted previously (not sure why all these cool utility pedals don't get the love!), but I noticed a used one popped up in my search at Guitar Center for $40.
Not a perfect solution for you because its not a one-footswitch solution, but you could definitely hit both switches simultaneously. Use something else to split your signal (like the Boss), then put something like this at the end of your FX chains and before the DIs and it could work. Bonus is you get a volume control for each channel right before it hits the board.
I see its also been discontinued like the Empress solution I posted previously (not sure why all these cool utility pedals don't get the love!), but I noticed a used one popped up in my search at Guitar Center for $40.

