I have been googling around for this... the thread about the multiple PSUs had me thinking. I have a 2 spare harddrives since my desktop motherboard fried itself, and I have an old PSU I could wire to power them, and I am sure I can scrounch up or make a power switch. The problem comes with trying to hook these harddrives up to my laptop. I don't want to pay for the IDE to USB cables, but I can't seem to find a guide on creating them on the net. I have made cables before (crossover, XBox controller to USB, NES/SNES to serial) but I don't know a lot about the hardware workings... and prefer to follow a guide.
If anyone knows of a decent one, I would love to try it.