The question still remains whether a module of any kind can be used effectively with the SK1 when it comes to changing leads between the two. Once this is answered, I can know which way to go. I can see that layering is what would happen, most likely. If so, it would be a question of r/h volume, I guess.

The following I know:
1. Rhythm is most important, and easily attainable either way.
2. modules would provide the rhythm and, at least, layering.
3. The SK1 has libraries of other acoustic and electronic sounds that I can very easily layer or solo on r/h. However, not the quality of good modules or kbs, I would guess.
4. As a compromise, I would reluctantly go with a second keyboard, but would rather have an SD40.

I appreciate everyone's thoughts, and would really like to know from you midi gurus the answer to the r/h lead question.