As long as the plane has no new features that require reprogramming of the game engine (like a real working norden bombsight, periscope rear guns, shrage musik, cluster bombs, or napalm), it shouldn't be all that difficult, right? It should just be a matter of having a 3d model and a flight model--not saying that either are easy.
both the bubbletop P-47s were introduced in patch level versions of AH, not full versions. Would be nice if we got a new plane every patch or two.