A new actor has been added to the Internet Movie Database page for Resident Evil 6. While this normally wouldn't be proof of much at all, there had previously-listed actors for the game have turned out to be true, some which were listed well before the first trailer was revealed. Still, it's worth taking with a pinch of salt.
Sam Riegel, the guy responsible for voicing Steve Burnside in the Darkside Chronicles, is apparently voicing the character again in Resident Evil 6. Now, it stands to reason that it's unlikely he'll be making it into the main game (last we saw him, he wasn't looking too hot), but if you add this IMDb listing to the rumour that new characters will be coming to the franchise's mercenary mode, this whole thing makes perfect sense.
Again, this hasn't been officially announced, so it's difficult to know for certain if it's true. It at the very least makes sense, which is more than the majority of rumours do, and so I'd definitely mark this as one to watch.
Source: Rely On Horror