Looks like the monoplane version of a Crimson Skies Devastator.You want unconventional, you got it: the Curtiss-Wright P-55 Ascender. The birdcage style canopy dates it to pre-WW2 (or early WW2).
https://en.wikipedia.org/wiki/Curtiss-Wright_XP-55_Ascender
There's one at Udvar Hazy; very cool looking airplane.The Dornier 335. 2 engines in a tractor / pusher configuation
French ace Pierre Clostermann claimed the first Allied combat encounter with a Pfeil in April 1945. In his book The Big Show (pp. 273–274) he describes leading a flight of four Hawker Tempests from No. 3 Squadron RAF over northern Germany, when he intercepted a lone Do 335 flying at maximum speed at treetop level. Detecting the British aircraft, the German pilot reversed course to evade. Despite the Tempests' considerable low altitude speed, the Royal Air Force fighters were not able to catch up or even get into firing position.
https://en.wikipedia.org/wiki/Dornier_Do_335
The one at Udvar Hazy