Most wireless mice are 2.4ghz and the dongle is just the mechanism that converts the signal to a usb signal (? Correct terminology is not my forte sorry!) There's no reason that a true bluetooth mouse wouldn't work with an built in bluetooth chip in a laptop - just double check the specifications.
Why do most wireless mice(sp?) require a usb dongle, rather than working off bluetooth?
And can you usually sync ones requiring a dongle with bluetooth on a laptop?
Cheers.