The need and the want are out there, nobody is stepping up to the plate despite everyone knowing the secrets to 100mpg.. no major manufacturers are mass producing vehicles of this nature.
All we would need is just 1 car, that looks like something production worthy and it will get enough attention to peak the curiosity of the right investors.
If i had a garage and more tools I'd build the entire car myself. There's nothing I can't build I just don't have the tools / garage to tackle such a project alone.
This thread may not go places, but it really could if the right people take interest in it.