Lifting body technology is an aerodynamic design technique used in the supersonic speed range originally pioneered by NASA in the early 60s for atmospheric reentry vehicles. Lifting body theory can be seen in the design of the Space Shuttle. The last Space Shuttle flight has already taken place.

I am not sure what MIT is thinking by making the ventral front flat in its airliner, but lift would be a minor reason. Weight savings would be my guess. An airliner cockpit does not need to offer a ton of space to house two pilots and their avionics, so drag created from abrupt curvature permitting, you would want to keep things small to save weight. Engineering is a battle between goals.

The top design has a low aspect ratio wing and stab, these are efficiency features to reduce drag. This would be squared off against greater structural stress so this design would have to be made out of wonderbread unless the materials are darned good. Therefore I guess it is predominantly composite. Composite is the future... no secret at this point.

Buried engines are a great idea but it requires freedom from engine maintenance, so you can shoot that one down. DeHavilland tried it in the early 50s and it worked awfully.

The RayBans on the top one are a joke. Nix that. Bird-repellant windows are the norm. Which one do you want to be behind?

Out of these 3 images I get the message that composite materials are the future- and I agree with that.