Take a look at the TSW Panorama. This is a light weight rotory forged wheel and is very similar in design when compared to the 607 series. This model is available in size 20x9 +30 and 20x10 +40. Here are the links with more details.
The 20x10 Panorama does have some concave to it but it sounds like the nerw TSW Sochi is what you're after. This model will be available hopefully in the next couple months. This model is also rotary forged and available in the same dimensions as the Panorama.
TSW Sochi wheels are very interesting. I love that look, similar to Vossen's. What about a 19x9.5 (or 20x9.5) and 20x10 (or 20x11) option. I would love more tire on the rear but I don't want to heavily modify the car.
2012 Shelby GT500
Stock suspension
Want Nitto drag radials out back and maybe 555 up front or NT05. (Only driven in nice weather and not worried about mileage)