Fallout: New Vegas lead Josh Sawyer has dropped a hint about a unique weapon in the game on Facebook. He first posted about unique weapons in general:

you know, placing unique weapons will never get old for me. i've been doing it since icewind dale and it's endlessly satisfying.

As a followup questions, he was asked "Placing them? You mean, like, on the mantel?", to which he responded:

pretty much. but instead of a mantle, it's some dusty post-apocalyptic shack on a hill with a john boorman's excalibur-esque skeleton kneeling in prayer next to a sniper rifle.