There seems to be a lot of this type kit car around (relatively speaking). I think they start with a big American car like a Monte Carlo which has a frame out front and just hang the front end fiberglas on it, insert cockpit area of your choice (have seen MGBs used for this too) then just hang on the rear fenders, bodge the rear and they are done.
Here is one with an MG Midget cockpit.
http://www.bobsclassics.com/85ji.htm
Many more here
http://www.bobsclassics.com/whatsin.htm
Not a high art form.....
Paul