not a chance. Even though Sony is a Big fish in the Blu Ray making, they still had to pay the other parties on every sale. I read an article way back saying that the royalties that Sony had to pay was the number one reason the PS3 was initially priced over $700.00.
Is MS goes Blu Ray
1) HUGE MS royalties to the enemy
2) Sony will know the exact date of the 720 release lol (MS won't show their hand)
I heard MS was looking at 3.5" Floppy drives