For a two seater why a trike at all. An autocycle is more simpler, aerodynamic, cheaper, and completely more awesome to build. Running a Ninja 250cc motorcycle engine would work great because this is completely faired in where as that engine has to deal with a .5-ish cd as a standard motorcycle. MPG for it would break 100-120mpg maybe more. You could get an autocycle below .17cd, and the frontal area would be far better than a side by side trike. Side by side seating is one of those weird things people insist on, but it's hardly a sacrifice especially when your already throwing out luxury, cargo, power, handling, and a spacious interior already for a high mpg econobox.
