If extenders are the primary issue...take a look at this product from Metra. [Link: metrahometheater.com]

Over 80' and works like a charm. We had a roof top swimming pool that got an outdoor motorized TV in the BBQ kitchen area. Florida so we were worried about the Crestron RMC holding up in the heat. We mounted the RMC in the attic and pulled the EHD cable through conduit out to the TV. It was just about perfect in length for our project. No issues with the cable.