I guess the Allion would sort of work as a Scion since it's kind of funky looking, but who knows. The tC was developed specifically for the US market and is not sold as a Toyota anywhere else, so I'm sort of inclined to think that the t2B will also be a Scion-exclusive car.
Or maybe, it'll be one of Toyota's several JDM-only mini-minivans, sort of along the lines of the Mazda5? Who knows?