Adding some more stuff is always fun.
Inspired by a recent blog-post on dangerousprototypes.com, I chose to improve the fan-monitoring. The unmodified device only monitors fan voltage, which is close to useless.
With the addition of a current-sense shunt resistor (1 Ohm, very easily done), one can measure the fan-current, which is not perfect, but might be expanded to true commutation-detection (true fan-speed).
This is just the first part, simple current-monitoring. It works nicely.