AHA!!! I think I found the problem + also solved the hand ghosting with AO problem I PM'ed you about b4.
I changed my newvegas resolution to native (1920x1200) and lo and behold, the double imaging disappeared. Moreover, the hand ghosting also disappeared.
The FPS counter now appeared at the top left corner and the text 'Fallout NV reloaded version 1.1.0' appeared on the bottom of the title screen.
So all this time FNV reloaded has been drawing stuff on the invalid portions of the screen although it is set to 1920x1080 through game-settings! Interesting though, as I have the same setup for Oblivion and Oblivion Reloaded and have no such problems there.
..... weird! NVR and OR has totally the same engine. It seems something linked to New Vegas. I noticed some strange differences between oblivion and new vegas while oblivion and skyrim dont. i dont understand how a game in the "middle" of others (oblivion and skyrim) has these weird mechanisms.