Gran turismo 5 does play in 1080p because I own and play gran turismo. It may not be exactly at 60fps but the frame rate is very smooth
GT5 is in 1080 vertical lines. its however half the horizontal res, so no, it's not 1920x1080, and thus not 1080p. it's upscaled to 1080 though. with the blurryness that a doubling of the horizontal res brings.