You can now get a slim-line Blu-ray burner, the Panasonic UJ-215, for your Mac laptop. The good news is that it works natively in OS X, and Toast 8 supports it. The bad news is it costs a whopping US$800. Below are the burn speeds.
DVD-R DL: 2X
DVD+R DL: 2.4X
The UJ-215 is pictured here beside its tray-load brother, the UJ-210.