Nintendo recently filed a veritable smorgasboard of DS-related trademarks in Japan. How many is a smorgasboard? In this case, it's forty. All but three of the terms are preceded by either "DS" or "DSi," and the mind can only boggle at the potential of some of these: DSiMovie, DSiMusic, DSiMail, DSArcade, DSBook, DSCreator, DSLive, and DSPhone were among the names that excited us the most. A full list is after the break.
Siliconera dug all of these up from the Japanese trademark database, along with a couple of other interesting tidbits, including potential English names for Tomodachi Connection (in which players get to be friends with Mii versions of Miyamoto, Reggie, and Iwata!) and Ritai Picross (Picross 3D), which we definitely wouldn't rule out for a western release.
Obviously, none of these might mean a single damn thing. Companies indulge in trademarking all the time, simply to protect future ideas. Time, as always, will tell.