Developer Steven Troughton-Smith seems to have discovered that running unsigned (custom) firmware—even firmware that bypasses the activation process—is super easy.
Not only can you use the Konami code to get the phone into dev mode, you can hold the volume-up button while it's booting in order to set it to restore mode. Once in that mode, you can use Palm's firmware flasher app to place on your own custom firmwares (doing whatever the hell you want to the phone) even if it hasn't been authenticated by Palm. Expect lots of low-level hacks that can do some really, really cool things. [Stephen Troughton-Smith via Daring Fireball]