> getting it stable with an external SATA drive would be cool.
> [...] How much success has there been with PATA drives?

SATA or PATA shouldn't make any difference as from the Mac's point of view it's just FireWire anyway. It's the FireWire bridge chip in the HDD enclosure that transparently connects to the SATA or PATA device. That is no different from USB where it also doesn't matter if it's a SATA or PATA HDD enclosure you connect to it.