Magician:
The really "ingenious" solution I've seen in the book:
"tinyAVR Microcontroller Projects for the Evil Genius™".
Author refers to Elektor magazine, December 2008(“LED Top with Special Effects”), (magazine probably would be easier to find in the library)
Motion sensor include two coils and OPA's, that sense Earth magnetic field. It allows to get speed, direction of rotation, plus synchronize leds for POV effects. Last feature is impossible to obtain with accelerometers or force sensors.
I'm not sure why hall effect sensors were not used in design?
Accelerometer wlll give synchronization, the centripetal force has a gravitational component that's a rough sinusoid(*) added onto a mean force - so long as its spinning in a vertical plane (if not it will be hard to see the PoV pattern anyway). High speed spinning will possibly drown out the gravitational signal, but smooth low speed circles should show it up nicely. Implementing a software PLL to pick out the phase will be an interesting problem too 
(*) the maths isn't trivial because the angular velocity isn't constant due to gravity.