I just read up on the ULN 2003 chip, and it looks like a great way to source 5 volts to each layer. It says it can source upto 500ma, that sounds like plenty compared to a single arduino pin. It looks like I hook ground up to pin 8, 5v to pin 9, and use the first 4 pins for input, and last 4 pins for output to each plane. WahBam plenty of current, with a few pins unused. If I had a ULN2803, I could pair up the 8 arrays into 4 arrays for twice the current.
This way, I can modify my old software for the cube to shift out 48 bits instead of 16, and it should work on this cube. I think i can probably use shiftpwm with this cube too.
Still waiting for new RGB LEDs to arrive... They are common cathode, I will use them to make a charliecube like asher glicks. I cant wait to compare the 2 cubes 