Go to Cigar Box Nation website and ask around there... Seems that site has become a haven for (OMB) One Man Band players...

I also perform as a OMB... I just use a single bass so that my other foot can play high hat and snare... Heel & toe... Of course there arer foot pedals that allow you to play bass with a second pedal that has linkage from one to the other... Musician's Friend sells them but the real estate around the left foot is so tight that I can't see trying to squeeze a third pedal in there would be of any value... There are also beaters with linkage that would allow one to play two basses with the right foot (left if you are a leftie) but no way to get them to alternate without lifting the right foot to another pedal which is cumbersome...

B~