Tekonsha Prodigy mounting
 

Got the controller and an '06 2500 Duramax, where's the best spot to mount it . (Rip, i'm counting on pics :D )

Just my $.02 but I hate seeing them mounted on the driver's knee panel. My controller is a 4-wire and I used a trailer wiring kit to make it a "quick connect" setup with the factory wiring harness. If you have a dash pocket, maybe it could go in there when in use, in the glovebox when not.
Not sure what the mounting options are for the Prodigy, but perhaps on the vertical part of the center console, down near your right knee.

Prodigy has a position sensor and needs to be mounted level. Mine is mounted under the right side of the dash just above my right leg. I've never hit it by accident.