A picture surfaced last night on Twitter (via Gootecks) showing what appears to be the character select screen with two placeholder silhouettes from an arcade location test of Super Street Fighter IV.
The possibility of new characters or "moves" was discussed by producer Yoshinori Ono in an interview with Japanese gaming magazine Famitsu, but Capcom would not comment on the rumor. It is believed that any new characters would be paid DLC for the console versions of the game.
Ono has been tweeting with fans asking for more information about this new image, but his responses have been carefully crafted to avoid revealing any information. A pulled forum post from community sites Shoryuken.com said that the two new characters would be Street Fighter III: 3rd Strike's Alex and Final Fight/Street Fighter Alpha's Rolento.
Ono is scheduled to reveal something tomorrow at the Street Fighter panel at Comic-Con with rumors putting it as a Capcom vs. Namco title, Darkstalkers 4, or merely new characters for Super Street Fighter IV.