A hoop house is basically a metal frame covered with plastic or other all-weather material.
VOA: special.2009.12.22
The frame is no longer assembled from laser-etched wood, instead there's a powder-coated steel framewith PVC plastic sides to help shield the various moving parts and lend an air of professionalism to the affair.
It masked the Galaxy S III ahead of its reveal last year in a blockier plasticframe and it could be that this phone, with a very Note-esque face and outline, is also a filler ahead of the final reveal.