I don't know of any official releases. But I would look at companies that have put out some convertibles as of late. I don't know enough to predict accuractly, but I sure wouldn't be suprised to see Toshiba have a go at the slate world after all these convertibles.
I think the thing is the money is probably in the convertible, maybe not true on this board but that is because the "more hardcore" tableteers are going to be on this board, and they are more likely to use slates. But Jow Blow is more likely to be attracted to the convertible model. I would have a feeling this, and the amazing products motion is already putting out (would be a long term commitment competing with them) is what deters the big companies from doing so.