CW entertainment president Dawn Ostroff confirms that there is nothing yet official, but they are currently examining ways to do it.
So...let's talk. Who could be spun off and how? Frankly, I don't think main characters including Dan, Serena, Blair or Chuck (and to a lesser extent, Nate, though of the core group I think he's the most expendable) are even options...as it would ruin Gossip Girl.
The obvious choice is Jenny. What do you think?
Other options: Vanessa, Georgina (who the CW has confirmed will return), someone else?