The 1st muscle car era I had a new 69 superbee & a 70 1/2 z 28.In the current era ive had a 06 gt mustang and currently have a 13 rt challenger do you think its feasible chevy will retro this platform in the form of a 66 to 70 chevelle ss 2 door and offer a 5 or 6 speed
Not likely. The Chevy SS/Holden Commodore is built on the Zeta platform, which is now at the end of its life (especially with GM shuttering the Elizabeth, Australia plant in 2017). It is offered in 3 body styles (sedan, wagon, and Ute) on the VF chassis and sedan only on the long-wheelbase WM chassis (Holden/Chevrolet Caprice), though, technically, the Ute is a long-wheelbase VF. Camaro is also built on a shortened version of the Zeta platform.
Next-gen Camaro (2015?) is reported to be built on the Alpha platform, which is shared with the Cadillac ATS, so when the Commodore dies in 2017, so will Zeta. I just can't see them investing the resources to build another body style for such a short run. They'd likely never recoup the investment.
Would they build a Chevelle coupe on the Alpha? Not likely since it would directly compete with the Camaro, though there are rumors of an Alpha platform Buick Grand National floating around. We'll see if that comes to pass.