There's a footswitch you should see that is made for keyboard players. It's called a "34oneII" (3-4-one-two) pedal and it's made by Ploytech. You can buy it from a motifator.com. It's a midi tap tempo switch that serves as a midi clock. You can hook it up to the TimeFactor and run a midi cable from the TimeFactor to the ModFactor and it sets the tempo that you tap into both units simultaneously. It only takes two taps (on beats 3 and 4) to set the tempo. Both units would have to be set to accept midi clock. I thought about buying one but didn't feel that I really needed it. It sells for about $170.
Using the external footswitch option is probably the best way to go for changing banks. I'm not sure, but I think that you can go up and down through the banks with a midi pedal, but you can't select channel one or two. I may be wrong about this. Check it out.