i think it’s a wp7.8 unit/prototype because of the windows (phone) 7 logo/button. The W(P)8 logo is different.

However, I would like the bottom to be smaller – like on the 900. I haven’t tried the 900 for at very long time so maybe it’s annoying but on the 800 i think too much space was “wasted”.
I have a Samsung omnia w / flash focus(us) and the bottom is quite slim and its very nice to have a small device, but still an acceptable 3,7″ screen. The Lumia 800 is more than a cm taller, though same screen size…

I can’t wait to see what Nokia and MS have in mind for the september event!