As a quick update, I got corrected timing information from the panel manufacturer:
ModeLine "1366x768" 69.30 1366 1398 1422 1432 768 771 775 806 -hsync -vsync
Please start X with verbose mode logging and check the EDID section. If it says this,
(--) NVIDIA(0): Manufacturer : AUO
(--) NVIDIA(0): Product ID : 8428
(--) NVIDIA(0): Manufacture Date : 2008, week 1
then please give the attached EDID a try with Option "CustomEDID" "DFP-0: /path/to/auo-8428-fixed-edid.bin". While the NoTotalSizeCheck workaround technically sets an invalid mode configuration, it does seem to work fine so people using that should feel free to continue using it. If you experience this problem and have a different manufacturer, product ID, or manufacture date, please let me know.
I'm trying to get a workaround with these corrected timings into a future driver release.