Monitor detection is broken for the laptop screen.
Try a variation of this:
Option "CustomEDID" "DFP-0:/proc/acpi/video/NGFX/LCD/EDID"
Option "ConnectedMonitor" "DFP-0,DFP-1"
Option "TwinView" "1"
Option "TwinViewXineramaInfoOrder" "DFP-0"
Option "metamodes" "DFP-0: 1600x900_60 +0+0, DFP-1: 1440x900_60 +1600+0"
This configuration in xorg.conf is for my setup, with an external monitor via HDMI.
The caveat is by specifying "ConnectedMonitor", monitor detection essentially breaks after you login (dynamic twin view no longer can detect changes to any of the ports).
There also seems to be a bug in card initialization when using the BFS scheduler. 3/4 of the time when you boot, you will get terrible performance. Con says that it's usually from real buggy code and that his scheduler is simply more prone to exploiting those bugs. There's nothing he can fix on that end.
NOTE: I'm very confused why the nVidia driver cannot detect the laptop lid when the EDID code is freely available from /proc/acpi/video/NGFX/LCD/EDID. Maybe the devs should look at how Linux gets the EDID data and contrast it with their own.