Meh - I sorted this out a few weeks back. Here's the results for anyone who likes to use nVidia drivers
It's a dual display: a) LCD, b) TV as separate displays I do this so I can play movies on the TV fullscreen using mplayers -fs option (and setting the display to :0.1) (and still use the LCD) The 1680x1050 LCD may have had problems before 2.6.20-1.2948.fc6 (well - it did but I'm not sure what changes I made to solve them)
Also note, ScreenX and VideocardY are not the same - I just didn't swap the names around :P
Section "ServerLayout" Identifier "Layout0" Screen 0 "Screen0" 0 0 Screen 1 "Screen1" 1680 0 InputDevice "Keyboard0" "CoreKeyboard" InputDevice "Mouse0" "CorePointer" EndSection
Section "Files" RgbPath "/usr/X11R6/lib/X11/rgb" FontPath "unix/:7100" EndSection
Section "Module" Load "dbe" Load "extmod" Load "type1" Load "freetype" Load "glx" EndSection
Section "ServerFlags" Option "Xinerama" "0" EndSection
Section "InputDevice" Identifier "Mouse0" Driver "mouse" Option "Protocol" "auto" Option "Device" "/dev/input/mice" Option "Emulate3Buttons" "no" Option "ZAxisMapping" "4 5" EndSection
Section "InputDevice" Identifier "Keyboard0" Driver "kbd" Option "XkbLayout" "us" Option "XkbModel" "pc105" EndSection
Section "Monitor" Identifier "Monitor1" VendorName "Unknown" ModelName "TV-0" HorizSync 30.0 - 110.0 VertRefresh 60.0 Option "DPMS" EndSection
Section "Monitor" Identifier "Monitor0" VendorName "Unknown" ModelName "CRT-0" HorizSync 30.0 - 110.0 VertRefresh 60.0 Option "DPMS" EndSection
Section "Device" Identifier "Videocard0" Driver "nvidia" VendorName "NVIDIA Corporation" BoardName "GeForce 6600 GT" BusID "PCI:1:0:0" Screen 0 Option "TVStandard" "PAL-B" EndSection
Section "Device" Identifier "Videocard1" Driver "nvidia" VendorName "NVIDIA Corporation" BoardName "GeForce 6600 GT" BusID "PCI:1:0:0" Screen 1 EndSection
Section "Screen" Identifier "Screen1" Device "Videocard0" Monitor "Monitor1" DefaultDepth 24 Option "metamodes" "TV: 800x600 +0+0" SubSection "Display" Depth 24 Modes "800x600" "640x480" EndSubSection EndSection
Section "Screen" Identifier "Screen0" Device "Videocard1" Monitor "Monitor0" DefaultDepth 24 Option "metamodes" "CRT: 1680x1050 +0+0" SubSection "Display" Depth 24 Modes "1680x1050" "1280x1024" "1024x768" "800x600" EndSubSection EndSection
P.S. careful - nVidia 'take' your money, you don't choose to give it to them - you might want to stay away from nVidia :D :D