The best way to reach future cafe standards
 

The best way to reach cafe standards in non-hybrid vehicles is high efficiency small diesel engines combined with aerodynamics, tire development and the use of regenerative braking paired with capacitor storage and electric pump systems.
Thoughts?

You've just described a hybrid.

Yeah its a double hybrid.
The turbodiesel is a hybrid and the electric system is another hybrid.
But don't worry the Ethanol Production Agency will make sure we don't ever have vehicles like that.

They could start by removing roof racks lol.

Make undersides of cars smooth.

Make back of car shorter than the middle, narrower as well.

Clutched A/C and PS or EPS.

Aluminum hood or trunk or more.

Shorter front section of car (steeper nose)

Cars can be shorter in general too

Beefy starters w/ capacitor banks and an auto-stop feature similar to G1 Insight

*EDIT*
Since joining this site every time I drive, every car I look at, I analyze the back of the vehicle and critique its aerodynamics.

Or a new Congress and president will just lower the Cafe standards, therfore the standards will be met.

That would work too.

BMW 328D does all of that and gets 43 MPG. Off the shelf

Only 43mpg?
We have cars on here from the 90s that can equal or better that and they never at any point cost any where near the $30k and up price of a 328D.

And the 2000 Insight can almost double it.

We can never return to the 90's. Current crash-worthiness standards in the US require too much metal to allow it. Compact is about as small as you can get in the US before you hit the law of diminishing returns.

I don't consider increased safety a bad thing, but to comply with both safety and CAFE standards, I don't think you can get around having to use some sort of hybrid technology, whether it be electric or hydraulic/pneumatic.

That being said, a lot of improvements have been made in engine and transmission technology. It is not unusual for mid-size cars, like the Nissan Altima, to get in the high 30's, combined, and over 40 on the highway. A lot could still be done, as has already been suggested, to tweak those numbers toward 50 mpg without hybrid technology, but I don't think we can solidly get there without it.