There are good ones with proprietary wireless adapters.
I think there are two reasons more mice don't use bluetooth:
1. BT still isn't standard on most PCs, so an adapter must be supplied anyway (though more are slowly adopting it)
2. BT is traditionally not as energy efficient as many of the propriety wireless systems. (BTsmart could change this)
If you don't want a dongle hanging off your MacBook or using up a USB port then your options are pretty much limited to Bluetooth.