Sorry, but guitars and keyboards are not the same game sound-creation wise. A guitars sound is VERY much a result of the touch of the player. With BB, well, He only changes a string when he breaks one! Dead strings may be the common thread with all of his guitars! And Willie----well, maybe nothing should be said, but Willie Nelson and BB King are two examples of the WORST guitar tones on record! Don't get me wrong, I have paid to see both perform and enjoyed them both, but it sure wasn't the guitar tone that I enjoyed! An electronic keyboard is not a "natural" sound,so in a sense, anything goes. Even a cheesy Farfisa sounds cool in the right context, like Smashmouths' "walking on the sun", and with electronic jazz I would imagine that the old Roland would be fine but you wouldn't want to hear any classic Bill Evans trio played on it! Just my two cents----
Bill