I don't know if this is useful for anyone else, but I posted a couple of scripts to rotate the display in Tiger on ATI Radeon-equipped machines.
[robg adds: Even though I have an ATI machine, I have no Rotate button in the Displays panel (no idea why not, though I can rotate using the ATI software), so I can't test these scripts. I have also mirrored the scripts on hints, so they'll be accessible in case the above link goes away.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20050723192722724