There is a company on long island That makes paddle shifters to retrofit into old musclecars. You build your transmission with a manual valve body (i.e. it doesn't shift unless you shift it - you don;t hvae to do it but then the paddle shifter will beat you to the punch) then install the paddle shifters and viola - a paddle shifted mustang, camaro, chevelle, GTO, cobra - you name it.
I thought about it long and hard, espically after seeing it on a 68 camaro, and I came to the conclusion that I don't like the idea. Retrofitting a new car is one thing but there is something fundamentially right about grabbing gears with a hurst stick (in my case in a dual gate shifter) that makes half the fun of owning a musclecar.