Esh,

You are right about the limitations of playing with LH bass + RH comping/melody. LH bass is just ONE great way to play a keyboard with its own limitations. Playing along with midi files - made with BIAB - is one of my favourite methods of practicing piano. For that I just need a synth with midi file playing capabilities, say an S90. Years ago when I was studying at the Yamaha Electone International School, I learned to play bass with the pedal. I didn't have the time nor the patience to develop this technique well, but managed to play simple bass lines. It's preferable over LH bass, as it opens more possibilities, but requires an investment of time to acquire a decent pedal technique. LH bass is limited in a solo situation, but it's great when interacting with other musicians in a duet or a trio.

-- José.