Airbus E-Fan
en.wikipedia.org
en.wikipedia.org
What is truly painful about the 172 is how an inefficient 60's airframe is still the goto choice for flight schools and first plane buyers. A modern 2 seat motor glider / LSA can be 1.5x faster, have double the range with an engine of half the power and fuel consumption. Also, that fuel is unleaded (avgas is leaded).
The lead issue has also spurred the development of turbo diesel aviation engines [1], which run on the more energy dense jet fuel.
There is hope that these next gen airframes and engines will lead to personal two and four seaters with mpg on par with sedans. Unfortunately though in aviation energy density is critical, and whilst there may be an argument for hybrid systems with an electric boost during climb, I don't think we will see electric personal craft in the near future. See Cafe for more on the state of electric craft [2].
[0] http://www.pipistrel.si/plane/wattsup/overview [1] https://en.m.wikipedia.org/wiki/Wilksch_WAM_series [2] http://cafefoundation.org
LSAs are a toy in comparison to the 172.
http://www.avweb.com/avwebflash/news/Did-Duwal-Beat-Airbus-A...