There will be nothing stopping Nintendo or Microsoft from using BluRay technology. The BR format isn't owned by Sony, they are just one of the keymembers that collects money from licensing.

When the next generation start BR will a much broader standard then today and as a strategy for becoming standard consortiums allways accepts new member with ease.

A BR-player in the next Xbox and Wii will only generate more money to the keyplayer.

Since Microsoft allready are working together with BR on diffrent levels they won't stop them. Like BR movies using MS backed technology VC-1.

I agree that nothing could stop Nintendo from using Blu-Ray, they won't. Mostly because, if you get technical, Nintendo isn't using DVD9 right now, and wasn't using MiniDVD last generation. Nintendo's used what pretty much is a cheap trick, by building what is 99% the same technology, but running a proprietary coding scheme and slapping a different name on it. Nintendo will use the "N6 Optical Disc" which will be a multilayer compatible Blu-laser disc that they don't have to pay anyone to use