I'm really starting to like the Claveau 7 CV Sport.
One could take a sand rail chassis with a mid-engine boxer. The transaxle would be shorter so the engine bay would be smaller and it already has side-by-side seating without the center tunnel.
Minus the roll cage, plus a stitch-and-glue body, deeper with shallow doors, and you're pretty much there. Moon Ripple hubcaps on 19s?