one of the developers who had attended the BB Tablet OS NDK webinar on May 12th had posted the slides on his blog, it is a nice read, check it out for yourself
Was a great webcast! Found that they appear to be offering a much deeper level of integration then was expected. Pretty excited about what will be possible! Also was neat to see them use the Quake 3 port as an example of how the nSDK works.
If you want to watch the whole thing, here's the recorded webcast: Lobby