Brian,
i put a RocketRaid 1522A into my G5 2.7 and it's been just great.
http://www.hptmac.com/US/categories.php?compatibility=2
it DOES NOT permit hot swap and it took a bit of hoop jumping to find the right pairings of eSATA drives and docks, but once configured, I have 2 full time eSATA ports and it was dirt cheap to do this.
In the 2 years since I did this, I would imagine there are more options.
NO issues with PT at all (currently like you, 8.0.1cs2, HD2).
Hope this helps.
J