You may want to read up some on this guy:
https://www.palatov.com
He was the first person to fit a V8 into an Ariel Atom and he and the guy who works in the shop next door (Tristan) have won some Pikes Peak titles in their time.
I have one of his cars, that Tristan did the major part of the assembly of. Great team and super hard working.
Check out all of his cars. One is a complete Carbon tub and frame.
You may also want to read up about the new Corvette. That might give you some ideas too.
I know you mention the 7, but perhaps using a new material may allow you to rethink the structure and layout.
Look how Ariel or rather Nick Smart, reimagined the Atom by taking a different look at the true user requirements and the materials at hand. That and a little lateral thinking (bringing in ideas from nature) resulted in something quite new and revolutionary.
What ever you decide, please keep us updated with your progress!
Edit: sorry, I'm not 100% sure they are still making the carbon version - you will have to check out the website!