I've been getting some pretty fun B3 or organ type sounds by using my bass, first through Quadvox on PF, then Rotary on MF. The key is to use the four PF voices similar to how you would use the organ draw bars.
For example, assign voice 1 and 2 to a 5th and and Oct up, then voice 3 and 4 to a 12th and 2 Octs up (or alternatively use voice 1 and 2 for octaves and 3 and 4 for 5ths). Then program the expression pedal to control the A/B mix. So you can either be fading in/out 5ths or the higher registers, like drawbars.