However in it tail less form I always felt (for a plane that carries passengers) it was a (stability) step too far. Then there was always the question of (ever decreasing) noise requirements (esp OR if ever used).
This 'C' version appears to address all these issues with its twin inboard tails. The cranfield built scale plane is based on a single passenger deck of about 450 PAX as I recall. Again this seems about right as an eventual 777-9/747-8i replacement.
The potential fuel savings for such a long range aircraft are staggering (circa plus 30% from todays aircraft).
Sadly I don't see it going into production over the next 20 years unless there is a military (Galaxy replacement) requirement.