I recommend you upgrade to Chameleon RC3 and try the GraphicsEnabler option. First, you should remove any injector kexts and the EFI string from your com.apple.Boot.plist.

This option will now, for nVidia cards, usually dynamically inject the proper EFI string for the card. To try it, just type "GraphicsEnabled=y" at the Chameleon bootloader.

If it works, you can add it to your boot.plist with:

<key>GraphicsEnabler</key>
<string>y</string>

It worked on an 8800 GTX and a GTX280 for me.