So the consensus is that the model is real. Whether it's indicative of a real project that is still ongoing is up for discussion. But many chinese boards discussing this model have been taken down, leading people to believe this model is reflective of something important in the PLA... or that this is some elaborate hoax (but no one has come forward to justify why this is a hoax yet, and the model is at a display in an exhibition. Short of PSing a picture or actually sticking a fanboy model in said exhibition, it's hard to see how a hoax of this scale could be pulled off)
So, if we follow from the assumption that this model is not hogwash, there are two (or three) possibilities.
1: We've been aware the PLAAF have had an H-X project ongoing for many years, with one proposal being a flying wing, one being a supersonic bomber. This model may reflect the latter. The consensus until a yesterday imho, was that PLAAF were going with XAC's flying wing bomber with the supersonic bomber scrapped. The model being shown could reflect a promotion of a "failed bid" just to promote the company. Or conversely (but not likely), the PLAAF may be pursuing both the flying wing and the supersonic bomber (supported by the idea that behind the supersonic bomber model is a very distinctive shape of a flying wing... that could either be the sharp sword ucav, or the flying wing H-X)
2: On the other hand, there have been persistent mutterings for a while now that SAC has been developing an Su-34 class stealthy striker/fighter bomber, commonly associated with a picture of J-15's designer inspecting a curious looking part of an aircraft or part of a mockup:
It's obviously a very curious piece of airframe, but it looks like it could make sense on the bomber, perhaps as part of the upper air intake which snakes down from the top, or perhaps the wing/body join.
From the picture of the model that emerged yesterday, (assuming it uses two WS-15 class engines) we're looking at a plane slightly shy of ~30m. That's much bigger than the Su-34 of course, but that's forgivable given it'll probably carry much more of its payload internally.
Basically we can reduce this model down to:
1: hoax
2: rejected H-X proposal
3: one of two H-X proposals with both being pursued
4: SAC's stealthy striker -- I think this idea makes the most sense. Also, if the flying wing behind the model is indeed sharp sword (instead of flying wing H-X), then this may be SAC's display, where they're showing off some of their sharpest offerings.