Ok, so it might not be totally a rumor. A new Total War is said to be announced on July 6-7, according to one of the developers.
This will most likely be shown first at Rezzed, let me see if I can find the link.
Edit: Here it is.
In the latest issue of PC PowerPlay (the same magazine that revealed Dark Souls PC edition), there is a teaser for the next issue and it is a picture of Rome: Total War. So it is believed that this will be for an announcement for Rome 2: Total War: