Hello..........I bought your OMB and just upgraded to version 4.
Your ideas about foot pedals should work. I took a similar approach. Before I bought the PSR2000 I used a Korg i40M arranger. It has great 4 variation arrangements and the ability to use the single finger mode to trigger chords. Last year I built a 32 note pedal board using a cheap mini-keyboard (Reveal Musicstar)for the midi interface. My original intention was to add the pedalboard to 2 keyboards and have a "virtual" pipe organ setup. I use a Roland SC8850 with the Roland Sound Canvas Pipe Organ Project (SCPOP) software. This is great stuff!
After using the pedalboard as a normal console organ setup I got to wondering if I could use it to trigger the style chords on my i40M. I read the Korg manual and set the necessary midi channels and it worked. I could play and change all the major, minor, and seventh chords while using 2 keyboards for awesome melodies ect. Of course I had to press 2 pedals to get the minor or seventh, but that wasn't a problem. Since you are only using the pedals to trigger the chords it shouldn't be a problem to use both feet, especially on a 25 or 32 note pedalboard. Just use the right foot on the upper pedal octaves while using the left foot to press any white or black pedal when desiring a minor or seventh chord. It doesn't take long to get used to playing this way. Just remember to have your split point set so all the pedals play the chords while the upper manuals play the right hand stuff. Good luck. -charley