During his panel at Comic-Con,Yoshinori Ono, producer of the Street Fighter series was interrupted by rival fighting game producer Katsuhiro Harada, of the Tekken series, to announce two new fighting games. One one is Street Fighter X Tekken, and the other is Tekken X Street Fighter. The was this is going to work is, Capcom is working on Street Fighter X Tekken, so it will control like Street Fighter, while the latter, is being developed by Namco and is going to control like a Tekken game. They showed a teaser trailer for SF X T, then surprised the audience with a playable demo of the game. They did not, however, show any footage, of the Namco developed version. A release date has not been set with Ono stating that the games won't be out "for a while" and people should enjoy Marvel Vs. Capcom 3 while they wait. Below is a youtube video of some gameplay footage from Street Fighter X Tekken. Enjoy!
http://www.youtube.com/v/N6U7jZ-qMfI&Source:
Kotaku