I live about thirty minutes south of Council Bluffs/Omaha. The only place I know of in Iowa is DaSu studios http://www.bonsaitrees.com/index.html
located near Kelley, Ia which is pretty close to Ames. I haven't heard anything either good or bad about DaSu so if you stop by let me know! The eggshell pots look interesting but that's an area I haven't even begun to get into yet.
If you're near Des Moines there is an exhibit at the Des Moines Botanical Center which I plan on seeing as soon as I can.
As far as Iowans go, when I left for the Army there was absolutely no way in hell I was ever going to come back to this place. After six years of being an airborne infantryman and spending time all over the country and on three other continents there was no other place I wanted to go. I don't like the extremes in weather here, I don't like being hours away from a major city(Omaha won't count as a major city until it gets a bonsai club!), but I do like the people.