I always check here first, too. I really never have anything new to add. I bought one of the 10rd magazines recently and can't get it to feed properly. I love my 20ga, and my wife uses it to dove hunt. Bet there are a lot more lurkers just like me.
I bought my 20 at a pawn shop. One of the local new/used gun stores just got both the 12 and 20s. No extra mags, just the guns. Check around again and again.