Mo.... Roland arrangers allow you to use MIDI program changes on a specific channel to trigger Variations and Fills (and Intros, Outros, and other stuff!), so you would hook the pedals up to the MIDI in, and program the pedals to send each function you need's PC when tapped. If you sit while you play, it doesn't take long for you to get used to where they are without looking (think about organ bass pedal players!). Standing is a BIT harder, but still easy enough (I usually stand, myself, and hardly ever hit the wrong button - and I've got seven!)

Behringer and Roland both make excellent, flexible MIDI pedals, although they can be a bit daunting for the beginner to program.... Find a local MIDI guru to help you out initially, and all should be fine.

BUT....... as in all things TRY BEFORE YOU BUY! Make SURE I'm not talking out my you-know-where before you part with your hard-earned cash!