Real Tracks in GT6 currently:
Fuji - Definitely not
Suzuka - Doesn't look like it
Daytona - Definitely not
Tsukuba -Definitely not
Le Mans -Definitely not
Nurburgring -Definitely not
Indianapolis -Definitely not
Monza -Definitely not
Laguna Seca -Definitely not
Spa -Definitely not
Motegi -Definitely not
Silverstone -Definitely not
Ascari -Definitely not
Willow Springs -Definitely not
Brands Hatch -Definitely not
Goodwood -Definitely not
Mount Panorama -Definitely not
The only real track currently in GT6 with some resemblance in Suzuka, and it's not very similar.
So that's a new track pretty much confirmed.
Crazy thought here: what if each round introduced a new track, and they have been delaying DLC tracks for a massive reveal here?