I've researched this for close to a full year, and you just echoed everything I've been hearing in that time. I think it's a no brainer for me. I just spent some time at my fav reptile store yesterday and they have 3 male Colombian boas there. 2 from 2011, and 1 from 2012. Their larger snakes are at the big show in Chicago this weekend I guess. However there was one 5' Colombian male there and he was big. I'm not used to the grown boa size and can say they are a lot of snake!!
I had great success with my son's BP from that store, and if I don't order a boa on line, I buy from go there. They are NOT a typical pet type store. They are a quality reptile store which makes me feel a lot more comfortable.