The last update I found on the mod was this:
"After my comment, I will ask a member of staff to close this topic.
We've been taken down because I took the site down. Dark0ne had nothing to do with it. At the time I put the message on the Whiteboards for everyone I didn't realize that I was able to do it myself, and thought only a member of the nexus staff could delete mods.
The problem is licensing. We need permission from both Bethesda and Obsidian to allow a mod like this to exist, one that allows assets from Fallout 3 to be used in New Vegas. It is not a Piracy issue. We didn't have permission, so the site must come down. Any mod like this without permission must come down, including RFCW and Deja Vu Vegas. "
It seems there's some sort of legal issue regarding it?