Cecil, Using a pair of fender mouldings would give a good shape both sides of the fender - as long as the fender chosen had a wide flat top, so that half the width of the fender could be cut off.
Grant's
new fenders with skirts (scroll down a bit) might well be just what is needed as it looks to be like the basic fenders are symmetrical, so the skirts could be fitted both sides.
The wheel pant photo used in the sketch above is actually described as "styled after late model Cessna 172". I think any aircraft wheel pant is going to be too small - no aircraft designer is going to allow a 2' high wheel pant (too much drag).
Don't look too much at the fender-to-body join on either the 3-D sketch or the profile/plan sketch of the Roswell - they are both completely wrong in this area. The fender only attaches well below the belt-line (max width line) of the body - so that bracket shown with tail lamps on it would actually be triangular and its bottom would be most of the width of the trailer!
To anyone interested in the Roswell, it's important to stress that the 3-D sketch isn't accurate - it's the trailer equivalent of one of those hot rod sketches with wheels 4' in diameter and width - the idea's the same, but the proportions are completely different.
Why hasn't someone built the paper model and photographed it yet?
Andrew