Thought this might also be some good food for thought. It's called the "Zoleco", there's a few threads about it here on Ecomodder. Some Canadian dude with plenty of time on his hands, but no financial support to 'go big' with his creation.
Started with a Suzuki Forsa, stripped it down, mounted the single rear wheel, and some basic outline of his final shape:
More rods, some backing material...
And after a few decades of sanding, priming, sanding, priming...
Says with the aero work, he'll need a mere 8.2 horsepower to cruise at 65mph. Your CRX is a good enough front already, can't really squeeze it any smaller than it is. But a simplified version of the Zoleco rear end might be up your alley.