I'd LOVE to make each LED individually addressable, but my major limitation is the fact that to cover a 1.2m tube evenly, I need to address at least 60 RGB LEDs - 180 LEDS!
Hmm ... if I addressed 'clumps' of 2 LEDs at a time ... 90 addressable locations needed. 3 LEDs at a time ... 60 addressable locations needed. 4 LEDs at a time ... 45 locations needed. I guess that's doable, but I would presumably require driver chips, similar to what everyone is using to drive their LED matrices. And that's a problem when my PCB is only 20mm wide!!
I will try to obtain a nunchuck accelerometer - the possibilities are enormous 
Do I literally just buy a wii nunchuck and nab the chip out of it, or can I buy them separately?
Another possibility I wanted to explore is having a microphone and beat detection - if you're performing in a club, having the colours react to sound would be amazing! I tried to breadboard this, but I just can't get a transistor amplifier to work. The trouble is that I'm working with such low voltages (just 2 AA batteries ... 2.4V with NiMH).