Something like the red cycle is what came to mind when I saw the title of the thread.
Bending down can reduce frontal area by a bit but not everyone wants to ride a bicycle with their head touching the handlebars.
I've thought about fairings along the side and wheels similar to the red concept above, with the driver sitting upright. A tapering storage area would be behind the driver's back, either for storage or a battery system for an electric bike. Maybe an aero helmet? although I'm not exactly sure how much aerodynamic benefit that would have.
I've always liked the idea of making an electric bicycle and improving the default horrible aero of a bike and rider, but I don't really have a practical use for one.