According to Joystiq, screen shots of Super Street Fighter IV's character select screen imply that 10 new characters will make their way into the series.
With only 6 of the rumored 10 new characters having been announced, we wait for more info on these other 4 characters.
"Every Street Fighter fan site ever perked up its ears late last week when Famitsu held a live streaming demo of Super Street Fighter IV. The administrators and visitors of said sites immediately began to pick the bones of the demo clean of important gameplay details -- the most fascinating of which comes from the above still image of the game's character select screen. The alleyway brawling enthusiasts of EventHubs.com discerned from said image that SSF IV will add 10 new characters to the game's roster -- four of which are still unannounced."
With only 6 of the rumored 10 new characters having been announced, we wait for more info on these other 4 characters.