I run my beer lines through copper pipes that run up into the tower, which are wrapped in insulation. If you have more copper inside your fridge than in the tower, they will act as heat sinks and keep your lines cool.
This is a nice idea. How do you run the power cord?
My temp controller is installed through the collar of my keezer, and I just wired the aquarium pump into the power supply for the controller since it's right there. If I weren't so lazy I would have drilled a hole in the collar and installed a switch.