Yea, Jeep has been throwing some stuff out there for the last few years, but like Red said, not too likely to make it to production. At least not any time soon.
Jeep Treo, electric AWD
The Jeepster, 4.7L V-8
How about the Hurricane? Twin Hemi's, and the ability to spin you to death like a 670 hp Gravatron.
I know the last 2 aren't fuel efficient, I just thought they are cool though. I really thought there were more concepts like the Renegade, I swear I've seen em in the magazines over the years.