I have a general feeling that if NISA was cancelling BRS, they'd be able to tell us. Somehow, I just can't see Image Epoch saying "Okay, you can't port the game, but you can't tell anyone you can't" unless they had some sort of good reason for it.
Like, I dunno, they're making a PS3/Vita port and that's what will be released instead, and they wanna keep it hush-hush, but they also don't want to make all their fans think the game won't be coming at all. I could believe that as a reason for the silence. But honestly? For NISA to outright lie about the status of a game they've announced? I just don't see that happening.
Honestly, I just think NISA is busy with other things, and their workload seems to not be slowing down anytime soon. By the time their done with the currently announced projects, they'll have Hyperdimension Neptunia V, Atelier Ayesha, Disgaea 4 Vita(I Hope?), etc. BRS is a project that is going to keep getting pushed back because they have more important things to do.