I don't think we will see it until this fall. Nintendo has too many aces up their sleeve in America as it is.
In Japan I think they released the peripheral just to stay afloat. Japanese gamers are an odd bunch and they don't seem to be content with the normal gaming fare these days. Japan is, afterall, the reason that the Wii even exists. It has been stated many times by Nintendo that they use the Japanese market to steer their company.
So while Americans may look at Wii Fit as a weird, gimmicky peripheral aimed at the uber-casual, in Japan Nintendo has to attempt these quirky risks or go the way of the 360 (ok...maybe not that bad.)
The good thing about this 10-12 month delay will be that developers get a chance to incorporate BB functionality into their games. Western developers will also get to gauge the possible success of the peripheral to see if it is a viable peripheral in at least one market. Granted, Japan is neither Europe nor North America......but it is a gaming market nonetheless.