If you are willing to drive to Lincoln and can manage to pin him down for a lesson, Dennis Schnieder would probably be a good guy to go to. I know he was teaching at UNL, but I think he's retired now. In any case, he's a nice guy and a great player and I think that he would have a lot to offer you.
I once attended a clinic he gave and he talked about growing up and playing trumpet in McCook, Nebraksa. He said he would run home after school every day, just to practice his trumpet and he practiced 3+ hours every day. My guess is that his approach to teaching might have a lot to do with simply putting in a lot of time in the practice room.
Another tidbit that came out of the clinic he gave. At the end of it, he played the Goedicke "Concert Etude" at about Warp 10, but light and clean, and he didn't miss so much as one single note. Not even a chip or a scuff - it's the cleanest I have EVER heard it played and I've heard it a bunch.