Well, as far as I am concerned,
http://wii.ign.com/articles/116/1163764p1.html the console is legit. While IGN reviews are opinionated, I have not seen them skew released informaiton. This article says that Nintendo themselves have said they are making a new system and will have a playable demo at E3. So, the idea of a new console is real
The rumors over its capabilities are questionable. Although, I imagine that they are still fairly accurate of what to expect. I mean, at the most basic level, I am expecting an increase in graphics capabilities. You rarely will get a large payday of selling old technology in a new skin. So present level technology or better is a must in the market. Xbox360 level graphics are what I expect to be available since the techology is well over 5 years old at least making it cheap, and nintendo seems to have always been about making stuff "cheap".
The 6-in screen thing... I wouldn't doubt it, but needs more details over why it would be useful. It's like the GBA & gamecube design taken to another level.