Well, you could:
a) Switch to OpenZaurus with Opie, it has a built-in on-the-fly rotation
Replace your Qtopia version with Qtopia 1.7, I think that it supports rotation (you\'d have to rebuild your rom for this)
c) There\'s another rotation app out there called \"qpe-rotation\", which doesn\'t rotate everything currently running, but will let you set the default rotation for the next app you start.
My vote is to go with OpenZaurus, if you are knowledgeable enough about linux.