Keep in mind that when I bought my 2011 WRX last year in July there were 0 (read it 0) on the lots in MN, WI, ND, SD, IL, MI, or IA. There were also 0 2010 on the lot.
You were LUCKY to get one that was on it's way in, and about 75% of Subarus around here were sold before they even hit the lot due to tsunami shortages. Many WRXs never even made it to the states in 2011.
I looked around for used WRX/STi vehicles as well, and there was only a single STi within 2 hours of me in the current body style. These are VERY hard to find used in many markets, but yours may be different than around here in MN. Both WRX and STi hold their value very well, so it really doesn't make a lot of sense to buy a slightly-used unless you really get a good deal on it.