Blu-ray laptops are add ons that range from 150-500. The Sony Z has a bluray read/write add on for 500, and the Sony FW has a blu-ray read only 150 add on, or I think a 300 read/write add on (not sure about the price on that one going off of memory). Those are tray loading and I'm all but certain that the huge price difference is due to the size of the drive. The Sony Z is 13.1" laptop and the
I believe Dell has a slot load blu-ray drive for 400, but as far as size goes, I don't know.
Currently the rumor is that the new macbooks are going to be all about the "brick". People are speculating that the power supply will include the power supply (duh), and an optical drive and maybe a few other things like an ethernet port or usb ports. If we have an external drive then I don't see why it wouldn't be possible that the next generation of macbooks could include external blu-ray drives and that 10.5.6 wouldn't come with the new macbooks along with hdcp. The fact that its external could simply mean it can easily be added as an add on.