Too bad you didn't get to go through Iowa. There is a playspot in Cedar Falls that is flowing enough for loops! It is called the "Clayhole" and you can look it up on AW if you like.
I have been lobbying the Cedar Falls City Council on behalf of the Prairie Rapids Paddlers (www.prairierapidspaddlers.org
) who are trying to raise money to improve the features in the river.
If you ever have plans to go through there let me know and I will put you in contact with Ty Graham who is hoping that at some point a rep will bring some demos to the area. (Another untapped market!)