Flectogon 40mm is surely not cheap, and Zeiss would hesitate to put their name on a crappy lens, but perspective distortion in it is damn noticeable. They have a beautiful rectilinear Biogon 38mm, but it is not on an SLR - the rear element of the lens is close to the film plane.
B) Perspective distortion and rectilinear-ity of lenses are two entirely different things. Perspective distorion has nothing to do with the design of the lens. It depends solely on how far you are from the subject, and not on what lens you are using. ALL lenses distort perspective. Its just that its obvious in wide angles because you can get really close to a subject while getting most of it in the frame.
Rectilinear properties of lenses on the other hand depend very much on their design, and therefore their cost.
Ignore A) in my response.