It's interesting what got made as kits and what did not. The O.S.C.A. MT-4, for example, was a simple and beautiful little shape and was a "giant killer" before Porsche unveiled the 550. The O.S.C.A. weighed mid 1300s and reportedly made 130 hp at 6200 RPM out of 1500ccs' displacement. Lots of races won (most notably Sebring in '54), lots of iconic drivers and owners (Sir Stirling; Briggs Cunningham, etc.). Very few made as they cost something like $10,000 new (compared to about $7,500 for a 550RS).
Oh yeah...and the brothers who made them? Their last names were Maserati.
Just eyeing this thing it's hard to see why you couldn't pop a mold off it and fiddle it up so that could be made to work with an old Datsun chassis, or even scratch-make something redolent that would fit a Midget (which has a shorter wheelbase) or an MGB (six inches longer). But afaik it's never been done.
Guys, if there were something that looked a lot like this that could be grafted over the ground-down remains of an old Miata without requiring an engineering Ph.D and/or yacht money, what would you think?