Thanks!
Here is something posted by Tumnus, Oct 03, 2003:
] Only OZ can do rotation on the fly because that has been added to Opie, which is open source. All the other ROMs use the
] commercial version of Qtopia which is closed-source and only has that feature on the SL-Cxxx devices.
So it looks as if the choice is only beween qt-rotate (which sometimes makes my touchscreen seize up until I reboot) or OZ (unreliable for the 5600). From what I have been able to glean from other websites, the tckrom rotation restarts Qtopia every time you use it. I suppose the reboot is a small price to pay for rotation. Perhaps best to wait for a stable version of OZ, then, if one is (hopefully) in the works?