Ed,
Sure, SATA is better. Adding PATA/SATA adaptors to interface those drives with a SATA RAID controller is a good approach, as would be a PCI FW 800 card/drive RAID setup.
My suggestion was simply a solution I've had direct experience with regarding John's original question concerning his G4 DP 1.25 MDD using existing WD ATA drives.
I did run the Master/Slave soft RAID (including the 4-drive RAID with boot drive in the ATA 33 optical bay) long ago, but didn't find that configuration reliable for working with 10-bit UC, which is why the 4-channel Acard was a good way to go a few years back. It's been very solid.
John, costs and other considerations come into play in getting more life out of an old (but perfectly useful) system. Lots of comparison info for various RAID configurations on:
http://www.barefeats.com/
http://www.macgurus.com/
...Tom
