So, depending on where you're willing to drill/cut/etc. there are a few spots. If you have a CB with a remote head/controller, you have more options. I've mounted the head of my ham to the top of the radio (in the little coin storage area). There are options from 67 Designs, ICS, and Bulletpoint for this location. I then just ran my mic cord next to the seat.
I've also seen other guys with clever mounts off the right side of the radio, cupholder, mounted from the pass seat with a ram mount that connects to the seat mount.
If you have a single unit where you need to see the controls, then you're more limited. I've seen guys mount either under the armrest, directly below the radio, or on either side of the console.