Well, in the media it is known as the Gran Coupe, and although being placed closely to the 6, is a different vehicle.
I'm assuming this leads the charge on the CLS, Panamera, Quatroporte and Rapide, and all the other '4 door coupes' as they've labelled them. Agreed though that 4 door coupe is a contradictory name, but usually means a few things.
1. It's fast
2. Rear legroom is sh!t, and there's usually only 2 seats, not the 3bench we're used to.
3. It's got a sloping roofline and all those other coupe-like design inspirations.
4. It's expensive.
5. It's hot.
My 2 cents, which're probably only worth 1 cent.
Must say I'm really fond of this. BMW has a reputation for building butt-ugly concept cars (anyone remember the concept for the 6 series:throwup

, and then they manage to get it right just before they finalise it. I think they do it on purpose to weed out the fashion victims (whom now drive audi's) :mmm: