It looks as if Rocksteady Studios - most recently of Batman: Arkham Asylum fame - are aiding in development efforts on the next Hitman entry, tentatively titled Hitman 5. An online resume page for UK-based actor Mark Sloan reveals that he provided motion capture services for the title. Conveniently listed next to that tidbit of info is the company responsible for contracting Sloan, which is none other than Rocksteady.
Considering the series has traditionally been handled by IO Interactive, we're not convinced that Rocksteady is operating on its own with this one. As Eidos owns a stake in the studio, they may simply be working with IO.
Eidos has yet to comment on the status of Hitman 5.