I heard a rumor similar to that when I was buying my new TV (!) at TigerDirect. I love living near their outlet stores. But yeah, I mentioned my 360 and the fact that they had a HD-DVD player + 6 movies for 70 bucks and how it finally died and all that, and in response he said it was out that Microsoft was making a Blu-ray addon.
Making a Blu-ray addon isn't entirely out of the question. Microsoft doesn't see it as a Sony product, as it isn't anyway, but as another business opportunity, and a way to keep their word about Hi-Def movies. I have both a 360 and a PS3, so I wouldn't need a Blu-Ray add on. :)