In the oct. issue of playstation magazine pg. 36
there is a very small article that says exactly:
MORE KOMBAT
In a speech at the RBC Capital Markets North American Technology Conference (or the RBCMNATC for short),Midway CEO David Zucker told attendees that work has already started on the seventh installment of the Mortal Kombat franchise and that it's coming for the PlayStation 3. Unfortunately, no additional details were revealed. Meanwhile, members of the MK development team were a little less specific but commented that it's probably not too far-fetched to expect a new Mortal Kombat game.
So there you have it folks, Mortal Kombat 7 is already in the works. If you don't believe me go read it yourself.