I guess an "unbuilt project" for me has to be a real project that existed and was studied by an aircraft manufacturer. However, once you accept a 3 view drawn by Air International you are departing from the truth, albeit minimally, according to the accuracy of the drawing and the talent of the artist. Also, not every "concept" released by a manufacturer is necessarily accurate or even depicting a real project.
Thats why I like everyone to quote sources when posting, as it allows you to follow up where the info came from.