Not exactly the midwest, but there is beauty in slope soaring at Torrey Pines.

Slope Soaring - Brookville, Indiana

Check out CSS members sloping at the dam, and here's a little background information available on the dam at Brookville:

Slopeflyer.com Article on Brookville Dam

The south side is the grassy slope.  According to this site, the dam is 181' high and 2800' long.  Winds out of the South is what is best, however those who wish to fly north winds may try their hand at "dynamic soaring".    

U.S. Army Corps of Engineers - Brookville Lake
TCSS Civil Air Patrol - 4 overhead views of Brookville Reservior Dam  

Slope Soaring - Frankfort , Kentucky

Our friends in Lexington and Louisville found this gem of a slope site.  Here is a writeup from AJ about the slope and directions.  

Slopeflyer.com Article on the Frankfort Slope

Related Slope Soaring Information

How Slope Soaring Works - Courtesy of the Atlantic Flying Club RSA

Slope Soaring Without Mountains - Why R/C is a good excuse to go to the beach.

Slope Soaring Basics - Courtesy of the Temple Hill Slope Squadron

Dynamic Soaring 101 - Courtesy of Charles River R/C Club