Some small time ago, Paul Vreede suggested that the Spacex Reconnaisance 2 ship might be based on the Blackbird SR-71 and the earlier YF12A spyplanes. Recent declassification of information by the CIA of photographs from Area 51 and the Skunk Works from 1963 show the precursor test vehicle - project OXCART or what would become the Archangel A12.
|OPERATION OXCART - ARCHANGEL A-12|
|BLACKBIRD RADAR TEST|
A great article on National Geographic shows the great lengths that the crews had to go to after an A-12 plane crashed in Wendover, Utah in 1963.
The super streamlined fuselage and silver finish have a much closer look and feel to the later Blackbird, but its unlikely the top secret OXCART programme could have directly influenced the Tri-ang designers, unless they managed to sneak past the security at the Skunkworks!