The idea is not far-fetched. Imagine Microsoft offering an external Blu-Ray drive? Through the years, most CD formats would require a special drive and now that the blu-ray era is upon is, you may say that it is one of the eagerly awaited devices and peripherals that techies are waiting for. And which company would be better to offer this other than Microsoft.
Of course there are the middle-class players who find ways of introducing drives that can read the new formats in the industry. But as far as Microsoft is concerned, the focus is really more on its gaming console, the Xbox 360.
If we look back at history, Microsoft had always come out with something to accommodate new games for its prized game console. So as far as reports are concerned, there is no doubt that they are reliable. There will definitely be one in the market soon and after that, expect a new game console that can read it.
It is just like a preparatory thing and an alternative so that game consoles can accommodate the fast paced change in CD, DVD and now Blu-ray compatibility issues which are only normal at the start.