FrozenCPU has a wide assortment of extension cables. I have three Antec 900 cases and I have needed an 8 pin extension for the CPU power plug on each of them. And I have needed extension cables for power and reset switches and drive LED's on two of them. I have been lucky enough that I haven't needed an audio extension cable.
The fans pull very little power, probably less than 1/2 amp, so they will not affect the operation of the drives.