multiplexing 8x8x8 led cube

[system]

For a school project, i am wanting to make an 8x8x8 led cube. Ive seen how to do this with shift registers (8 to control one layer, and 1 more to control the cathodes of each layer). i was thinking of a way to reduce this down to 3 shift registers, and was wanting a little input from you guys to see if you think it is feasible or if im insane :P. i want to have one 8x8 layer controlled by 2 shift registers (multiplexed) and 1 shift register to control the 8 layers. in a way this would be one shift register for x, one for y, and one for z. i have a simplified down diagram (3x3x2) which i hope should clear things up a bit

so uh, tell me if I'm insane!

[system]

I don't promise I'm right, but that looks like it should work. Pretty sweet, actually.
One drawback being that your duty cycle will be 1/64, instead of 1/8. You may be able to compensate by overdriving the LEDs.

[CrossRoads]

Here's a 5x5x5 I did, you would expand it 8x8x8.

Fellow who was doing it wanted discrete transistors.
I think I would use TPIC6B595s for the NPN drivers instead, its a high current sink shift register.