I had a Adaptec SlimSCSI 1480 for my Pismo. The drivers never left beta as far as I know. They worked with the caveat that it wasn't hot pluggable (ie, once you put the card in, you couldn't remove it until you rebooted - under threat of KP). I never used it past 10.2.4, so I am not sure what's up under 10.2.6
Sorry I didn't have better news.
-- Jason