I was shocked to see what some breeders charge for their seeds when I first started looking at them a few months ago. You're absolutely right, it's ridiculous...Doggies Nuts (sold through Attitude) is another breeder that's pricey, not quite as pricey as Dr. greenthumb though.
There's a couple people on here that breed and do an excellent job of it too that should sell their stuff but they don't. One I only know breeds because I ran into him at the local hydro shop and got to chatting with him (small world). Now I have gotten to know him a bit and have seen the finished product of a couple of his strains and some pics of the plants it came from which look incredible. Rumor is that he grows large amounts of some well known strains too and sells to a couple local clubs to finance his hobby. I can't confirm it though because he's pretty tight lipped about his business, as we all should be.