
There have been plenty of rumors though. but that's just it: RUMORS.
According to the article, the new hardware will include a camera and music playback functionality. The camera will be integrated into gameplay, which suggests that it may be more of a new system than an upgrade. It also features the ability to connect with "information terminals" to get location-sensitive information, which we know Nintendo has looked into. There's even more in the print version of the same article. It states that the device will cost less than 20,000 yen.
Nintendo have commented on this.
“The Nikkei newspaper wrote a recent story about a DS solely based upon their own research and speculation, without interviewing Nintendo. While Nintendo is always working on new hardware, we have not made any announcement about a DS and we cannot comment on the Nikkei story.”
They can neither confirm nor deny these claims, but it also seems like the new DS screens have been leaked (above).
I don't know what's going on but Nintendo is being pretty tight lipped about it all which of course arouses suspicion.