That is so cool...I used to have a Roland VK-1000 (basically a 76 note organ) and the pitch bender lever would activate the Leslie speeds (just like the old Hammond half-moon)...that was a great instrument, and it also doubled as a pretty good controller as well.

The mod wheel sorta feels natural to change rotary speed, because of that effect's close relation to adding vibrato to the tail end of a note or phrase.

The thing I didn't like about joysticks, was they seemed too exposed and too easy to damage.