It looks like CD Projekt Red, the highly lauded Polish developer of The Witcher 2, is looking to expand in light of their new found success. Their website now has an entire category of their job listings page devoted to an "RPG in a brand new setting."
The listings are pretty standard for any project - environmental artist, gameplay designer, quest designer, animator etc - so it's difficult to glean any information from those listings. However, given that the "RPG in a brand new setting" stands alongside another category called "RPG in a dark fantasy world," makes us think CD Projekt Red is beginning work on a non-Witcher-related project...as well as a Witcher 2-related project.
We wont know anything until the developer decides to make an official announcement, but as always, we'll be looking forward to E3 for a potential announcement. Last year the developer had a fairly large presence at the show, so we wouldn't be surprised to see them make another announcement now that The Witcher 2's Xbox 360 version is out in the wild.