By looking deep into the files of the Benchmark tool that was released early in the week, users found some audio data of the announcer mentioning T-hawk and Deejay. This, of course, created hype and rumors that both hawk and Dj are going to be playable or hidden in the pc version of sf4. Unfortuantely Seth Killian denied the rumor and explained to Destructoid what is going on.
Seth Killian: "No, T. Hawk and Dee Jay aren’t coming to PC SFIV.And just to stave off the rumor train here, no, that doesn't mean there are a bunch of finished or semi-finished characters sitting around just waiting to be added as DLC or something. The level of polish, balance, and refinement that went into SFIV should hopefully make clear the difference between putting in wireframes and some rudimentary collision and being anywhere near a finished, living, breathing SFIV character. "
So what were those files? probably left overs from the developement process, since it has been known for months now that both Dee Jay and T-hawk were planned and even had 3d models but were scrapped due to time constraints.
I would not expect to see t-hawk and deejay in SF4 anytime soon, especially that, Rumor has it, a new SF4 sequel/itteration will be announced during the Tougeki tournament in August.