Nintendo.com has posted up some information regarding its next generation console, what is interesting to note is that the description reminds me of a Playstation 2!

In its final form, Revolution will be about the thickness of three standard DVD cases and only slightly longer. The versatile Revolution will play either horizontally or vertically, allowing the user total flexibility in setting up a gaming session wherever they have a television.

Dont know about backwards compatibility but it sounds more like a step back.