So I came to the conclusion that it really is getting close to the time that Rihanna would announce a new single. I highly doubt it will be for R8 though, we'd have heard at least a FEW producers talking about working with her, or people like Ne-Yo saying "I hear she's back at it." We got all that plus more leading up to the releases of Loud, TTT and Unapologetic; starting even in May.
But I think she'll just end up re-releasing Unapologetic in November. The only person we've heard she's working with is Nicky Romero. They can easily do 2 tracks together, then she can add another track with Stargate on there. Rih doesn't have the time or the interest to promote a new album, or her previous one at that, so a re-release is really the only way to go at this point.
She'll be dropping the same day as Brinty too.