Holiday update w/ new Mesh Map
http://www.naughtydog.com/site/post/uncharted_3_holiday_items_and_block_mesh_lab_map/
edit:
For those of you wanting to complete the Arena treasure sets, I've seen a few posts over at the NDF that may confirm a treasure theory of mine. The treasure system seems to take into account which rare treasures the players have/don't have. So, in order for a new treasure to drop, you need to be playing with at least one other person that needs that same treasure. Looking back at all the times I've gotten new rare treasures in Arena, it was always with either low-level players in matchmaking (confirmed they didn't have it before via PM) or friends that were also missing that treasure. Additionally, I have played a lot of Arena with a friend who has all of the treasures, and treasures drop as if he was a low level with no treasures. Accordingly, I think it's safe to assume that no sets completed and all sets completed is treated equally in this treasure drop system.
tl;dr:
Play Arena with people who:
-have no treasures
-have all the treasures
-need the treasures you need
Worst case scenario, get two friends to create alt accounts and have them play Arena exclusively with you.