I've now had a chance to try out the ideas Hagstrom sent me (see the 4/10 post) for getting my Tornado spinner working with the ME4. They didn't work. At least now the voltage on the spinner sensor lines is changing but the levels are all wrong (the low level is about 2.2V and the high is about 3.5V). So I wrote Hagstrom back and they suggested that I increase the value of my pullup resistors from the 1K they suggested. I think this may work, but it might be simpler to just build an active high optical encoder board for the Tornado. I've already got all the parts (two optical interruptor sensors, a resistor, and a 4 contact 0.1" header) I need to do it and the circuit is pretty simple; then I won't have to worry so much about resistor values and voltage levels.
Incidentally, I hooked up one axis of my trackball to the spinner input on the ME4 and it worked fine. So at least the spinner channel isn't fried or anything.
UPDATE: I breadboarded the active high optical encoder circuit last night and it seems to be working. Now I just have to solder it onto some perf board and mount the board to the spinner. I'll probably post some pics of the finished product and the circuit schematic after I have it done.