A heavily illustrated USAF brochure on turbine engine technology included, among a vast number of little photos of engines and aircraft, a few illustrations that might be of interest.
Several futuristic concepts here, several old ones. Of particular interest is the “Supersonic Multirole Fighter,” which looks like a cross between the old Lockheed Hopeless Diamond concept and the Northrop XST design… tailless with an inlet on top, with features reminiscent of the F-117, but blended rather than faceted.
Of these “Emerging Concept Needs,” several are distinctly old. The middle row of three designs are all 20+ year-old concepts.