> I've heard that iPads support a Bluetooth mouse now, but I don't have any personal experience with it. I haven't heard anything about trackpads.

They do, but it's emulating a fingertip (for accessibility), not a proper mouse cursor. It was neat to play around with for a little while, but not something you'd want to do over a longer term.

iPads will also work with Apple's Magic Touchpads (the standalone units), but they must be connected via USB, and the same finger-emulating touchscreen caveat applies.