Solution for a longer ethernet to thunderbolt adapter

I am trying to create a docking station in a shared office space. All the users have the same Mac Book Pro 15" 2.8GHz Quad-core Intel Core i7. In the past, we have just run an ethernet cord up through the table base and user sit at the table and plug right in. When we purchased new Mac Books, we needed to make use of the ethernet to thunderbolt adapters. These began disappearing because you can just disconnect them and walk away. I would like to attach the adapters in the base of the table and then run them up to the table top. They are too short for this. We tried using thunderbolt extender cables but these are not reliable. Does anyone have any other ideas?