Would be easy to build I am guessing, depending on how detailed and how big you wanted it. A stretched out versa wing under an again stretched out fuse and some EDF's... anyone got some EDF's layin around?
There's no FT official Concorde but its a fairly popular scratch build choice from everything to single prop-slot foam parkjet pushers, to single EDF larger foamies, to huge multi EDF and even turbine that are wood and fiberglass and carbon fibre.
My effort in 3 mm Depron with 4 x 40 mm EDFs
Only 34" span but its 80" long!
No undercarriage so its hand launched. No so bad as it only weighs 24 oz!
Practical? No. Worth the time and effort to build? Definitely not! But is does look good in the air and it flies as a realistic 'airshow' speed.