John-
I think Scott Aviation out of KDPA used to do some traffic watch. I'm not sure if they still do that anymore, but you may want to check it out. There are (or were) two parts to Scott Aviation - the charter and flight school. I'm pretty sure Illinois Aviation Academy bought out the flight school, so that might be the one you want to ask. They are still in the old Scott building on the northwest part of the airport on Tower Rd.
Good luck- hope this helps!
I