An enterprising Vaio P user, "DaHarder," seems to have gotten Leopard running on it, though not everything works. This creates a Mac that weighs 1.4 pounds, has a full-size keyboard, and fits in a (large) pocket.
Unfortunately, it's referenced only obliquely, from another thread. DaHarder, if you're reading, tell us how you did it!
Source [Pocketables Forums]