Its been posted. I think it sounds more like BMW's B58. :dunno:
http://www.supramkv.com/threads/2018-toyota-supra-spied-testing-on-the-nurburgring-nordschleife.617/page-4
http://www.supramkv.com/threads/2019-toyota-supra-spied-with-production-lights-amidst-gazoo-rumors.679/page-2
Guff just updated his OP on this matter. But I don't think the concept was scaled up for show like with the FT-1. BMW designer has stated the new Z4 will have a longer wheelbase than the outgoing model and that the concept's proportion will carry over to the production car.
Sadly Toyota is just a tight lip company in general. BMW on the other hand is definitely more forthcoming. They have already confirmed the start date for production and stated in their Z4 press release that we will see their production car in 2018. Toyota... crickets...
Another prime example...