Oh my god! I just realized leopard really does this! I have it on my powerbook since one and a half weeks and thanks to this thread I just discovered it! My machine is the 1,67 ghz model with the 1280x854 screen.
I don't know if this will work for the 1,5 ghz pbs too. Maybe clone your hd on an external one and just try it?
As for upgrading to leopard, I was really impressed. I just upgraded and did not reinstall completely. It took about 5 mouseklicks and 1 hour of waiting. No crashes or any weird behaviour so far, and the machine feels snappier than with tiger. Oh and I have much software installed, Adobe CS3 Design Standard, Cinema 4D, and lots of little helper programs. So far this has been a more easy than expected upgrade, and now I even get the 2 finger click hurray! 🙂