TV-Out clone display works for me.
 

this is my xorg.conf file for tv-out at cloned display.. works perfect =]

Section "Monitor"
Option "CalcAlgorithm" "CheckDesktopGeometry"
HorizSync 30 - 50
Identifier "Monitor[0]"
ModelName "PRESARIO MV500-"
VendorName "COMPAQ"
VertRefresh 50-90
UseModes "Modes[0]"
EndSection

Section "Modes"
Identifier "Modes[0]"
Modeline "800x600" 36.88 800 832 912 1024 600 601 604 621
Modeline "800x600" 44.13 800 840 920 1040 600 601 604 624
Modeline "800x600" 51.73 800 840 928 1056 600 601 604 628
Modeline "800x600" 55.88 800 840 928 1056 600 601 604 630
Modeline "640x480" 23.06 640 656 720 800 480 481 484 497
Modeline "640x480" 27.74 640 664 728 816 480 481 484 500
Modeline "640x480" 32.64 640 672 736 832 480 481 484 503
Modeline "640x480" 36.97 640 672 736 832 480 481 484 505
Modeline "1024x768" 65.00 1024 1048 1184 1344 768 771 777 806
EndSection

# ************************************************** ********************
# Graphics device section
# ************************************************** ********************

Section "Device"
BoardName "GeForce4 MX 440"
BusID "1:0:0"
Driver "nvidia"
Identifier "Device[0]"
VendorName "NVidia"
Option "TwinView"
Option "TwinViewOrientation" "Clone"
Option "SecondMonitorHorizSync" " 30- 50"
Option "SecondMonitorVertRefresh" "50-90"
Option "MetaModes" "800x600, 800x600"
Option "TVStandard" "NTSC-M"
Option "TVOutFormat" "COMPOSITE"
EndSection

# ************************************************** ********************
# Screen sections
# ************************************************** ********************

Section "Screen"
DefaultDepth 16
SubSection "Display"
Depth 15
Modes "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 16
Modes "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 24
Modes "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 32
Modes "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 8
Modes "1024x768" "800x600" "640x480"
EndSubSection
Device "Device[0]"
Identifier "Screen[0]"
Monitor "Monitor[0]"
EndSection