Well, it's not really a driver; Lennart has been very patient with me, and
I now have a working userland program which connects to ugen0 and "drives" the
powermate.  I don't entirely understand the rules for "pulsing" - it has
the ability to pulse, and I can control how fast it goes, but I think I'm
missing some key component of the data sent.

I can receive clicks and left and right movement from it, anyway.

So... anyone interested in playing with one of these, or have suggestions
for what a driver for something like this should be able to do?

-s