I am probably the perfect target customer for such a vehicle.
I had become a "Toyota Loyalist" before becoming infatuated with EV drive-trains.
I still own a Supercharged MR2 & Lexus IS300 (sort of a 4 door Supra) as my long distance trip ICE cars.
Of all possible brands to pick, Tesla and/or Toyota would be tops on my list, so if either one comes out with something IS300 sized that uses a Tesla (Model S style) drive-train, I am ready for that to be my next car.
If it approaches 300 mile range, offers DC/QC/Supercharging, and has sports car like performance, I will likely get rid of everything else (MR2, IS300, LEAF) and finally just have one car again.
Come 2015, it would be a nice dilemma to have... Do I get the Test BlueStar GenIII, or the electric Toyota Supra?
If they have shared DNA, it might come down to styling/features/pricing/...