Well, now is perhaps the time to say that I actually have SME6.5b2 running on S-ATA.
Install went a treat - but, mind you - first I had to make the mobo lie to the installation, representing the drives as legacy IDE instead of S-ATA (ie. compatibility mode).
The actual installation on two 120Gb disks (RAID1) took all of 6 and a half minutes.
Right now I'm having a go at the update scripts.
Step 3 is running and to my best knowledge nothing is broken as of yet.
The exciting part will be step 4 !!
. . . so, richW - 6.5b2 does run on S-ATA, so far without a glitch !
To forego the obvious question, the mobo is an Asus P4P800-MX, running a 2.4/533 P4, with 1Gig PC2700-RAM (since my Abit IT7-Max2 couldn't cut the custard).
I've put the two drives in Cremax cooler-boxes, just to be on the safe side.