AJB2K3:
Stupid additional question but I plan on running this of a 3.6v PSP battery (always have 2 spare in camera bag + 1 in each of my psp1001 consoles)
The voltage is in range for the TLC5940.
The voltage is slightly out of range for the AVR processor at 16 MHz. Many many people run the processor slightly out of the voltage range. I have never read about any problems. You will have to use your own judgement. Obviously, if you were building a pacemaker, you should choose a different path. If you were building a light display, running the processor a bit out of specifications is not a problem.