Douglas (possibly) airlifter model, perhaps related to MPLE program

[Jemiba]

The inverted gull wing may just have been a proven method to reduce the
length of the main gear legs, which probably would have been housed in the
forward parts of the inner nacelles.

 

[Vahe Demirjian]

Tried a quick and provisional sketch from what I can see on those photos. The wing is
quite far aft and the "radome" could be either a clamshell or a swinging nose, I think.
The large pods under the kink of the wing probably house the main gear legs.
Transport glider seems quite plausible to me.

This drawing is a bit outdated because it omits the four turboprop engines seen on a desktop model of the transport design (see replies #11 and #21 for photos of the model [a photo is also on page 34 of the book American Secret Projects: US Airlifters Since 1962]).

 

[tab28682]

I have seen an old model of this configuration at General Dynamics Fort Worth over the years. My best guess is that it was the "Heavy Logistics System" (CX-HLS) (previously CX-X) proposal for GD. Model is still around today.