I bought eight level 81 items last night, and when I opened my mail this morning they had all sold. I think Gimp (@GimpsGold) originally came up with this theory of selling level 77-80 greens. If you were level 77 you could equip cataclysm greens that had much better stats than their WOTLK counterparts. This meant you could level faster and destroy people in the Battlegrounds. These cataclsysm greens had high ilvls allowing you to get into cataclysm dungeons like Throne of the Tides and Blackrock Caverns faster. No need to spend lots of time upgrading all your wotlk gear via quests. Instead you could save some time and get straight into the new dungeons. Jim and Alaeriel have mentioned having success wih 77-80 greens on their livestreams www.twitch.tv/jimyounkin and www.twitch.tv/alaeriel .
Majority of the items I sold were shoulders and chests, now why were people buying these level 81 greens? Surely if they wanted to buy items they would have bought them in the 77-80 range. However I then remembered that Wotlk BoA armour stops giving bonus XP at 81. So maybe some people are still wearing the shoulders and chest for the bonus XP until they ding 81. They are then upgrading once they hit level 81, buyers are thinking that there is no point buying a 77 green because they are already level 81 and can equip greens with a higher ilvl.
I’ve bought 10+ more level 81 items today and will track how fast they sell; I am only going to buy shoulders and chest from now on. Just thinking about it maybe Level 81 weapons could be something to look into as the boa weapon are 1-80 like the shoulders and chest. When someone goes to the Auction house to buy some level 81 green armour they might look at the level 81 weapons as well?
Use Armor/81/81/i272 in Auctionator and try shoulders/chests out first.