HIP, never go full retarded...mid engine vettes are talked about every new generation. Never going to happen. THe Front Mid layout just gives way too much trunk space to give up.
A DOHC engine can be made lighter than an LS engine. The Coyote is lighter than the latest crop of LS engines. I can be done, it just takes clever packaging. THe cowl height is such a meaningless statistic. Aesthetics can be made to look fabulous with any engine.
I would take increased efficiency over cowl height.