Well I once again was distracted by a Team Fortress event - Australian Christmas 2011. They had a 'contest' similar to the one in summer where you can win prizes by getting achievements in various games. Only in this case the prizes were pretty much just coupons and coal (7 pieces of coal could be crafted into something, most likely another coupon). Later it was revealed that there were also hats that could be given for getting some of those achievements. I played every game I could that was free, with the one exception of Toki Tori, which I got for free as a prize for getting an achievement in some other game. Still, all I ended up getting was a lot of coupons, most of which I have no use for what so ever. I did get a copy of every game Valve developed in 2011 as well as a copy of Half Life Episode 1, but I already have that, so it hasn't done me much good.

What I was really after was the B.M.O.C. (The Big Man of Christmas) hat, which is a Santa hat. It seem like that should have been one of the first Christmas hats ever released, but they waited until this year, and they made it extremely difficult to obtain.

Well I once again was distracted by a Team Fortress event - Australian Christmas 2011. They had a 'contest' similar to the one in summer where you can win prizes by getting achievements in various games. Only in this case the prizes were pretty much just coupons and coal (7 pieces of coal could be crafted into something, most likely another coupon). Later it was revealed that there were also hats that could be given for getting some of those achievements. I played every game I could that was free, with the one exception of Toki Tori, which I got for free as a prize for getting an achievement in some other game. Still, all I ended up getting was a lot of coupons, most of which I have no use for what so ever. I did get a copy of every game Valve developed in 2011 as well as a copy of Half Life Episode 1, but I already have that, so it hasn't done me much good.

What I was really after was the B.M.O.C. (The Big Man of Christmas) hat, which is a Santa hat. It seem like that should have been one of the first Christmas hats ever released, but they waited until this year, and they made it extremely difficult to obtain.

I didn't see anything during the Christmas event that said unlocking achievements would result in hats. I think you may have been misinformed.

At this point in time, the B.M.O.C. is selling for 6-7 keys (or approximately 17 refined metal) in the trading community so your best bet might be to try to win it in a raffle.