We don't know wether the DS version was in production before, wether it is even being made, or wether it will just have bonus 3D capabilities on the DS' successor. It was listed by the old name, Spyro's Kingdom, after all- since a 3DS version is in production(see below), it may have simply changed to the newer console during developement, and the DS version may have been dropped. No regular DS version under the new name has been mentioned yet.
Quote: Kotaku
The Skylanders toys can also be made to connect with more than just the Wii, which Activision made clear from the get-go. Executives said they want to put the game on multiple platforms. A 3DS version, for example, is also in development and will connect to the same toys. The intention is for a single toy to be connected to multiple games and to always carry the player's stats to that toy.
Right now- we only have the Wii and 3DS versions confirmed. All other major versions are likely. It was also leaked it would be for the PC, but under the older name(if I remember correctly). Additionally, a version was announced for "mobile devices".
Also- look at this: http://search.gamespy.com/prod...o%27s+Adventure
Feel free to post your own finds.