Hi Rocco,
Used your method(outputting chords to arranger k/brd). Works beautifully,
BUT the keyboard (say like a Yamaha PSRxxx)then plays its idea of a bass
pattern-- I gotta tell you this ruins the tune for a real time bass player.

I've built on your idea,BUT to use the endlessly capability of BIAB to
produce pleasing,and SPECIFIC lines for each tune.(All blues,Time is tite etc).

On my PSR you can assign all BIAB parts to PSR parts as incoming midi.
Then you START(sync on) just the drums. [No need for left hand split].
You can now control tempo & pitch from QWERTY, and which voice(s) for each
part on the keyboard, apply DSP,EQ,and save as registration buttons. Bonus
is U can splat the arranger drum fills randomly,rather than at fixed bars.

I hope you're your still about for this six year old reply. You can have my
URL anytime or any demos etc.
Regardo,
jonW