Brian, Have you thought of tapping into one of the fuses in the fuse panel? There are "things" that you can buy at the auto store which allow you to add a second fuse to an existing fuse. Plug it in exactly where the existing fuse is, the original circuit isn't interrupted, and you get a new fused circuit to boot. (Perhaps someone else could post the proper name, so you'll know what to look for.)
You could use an existing circuit which is always hot or one which only is powered with the key in ACC.
It's also pretty simple to run your CB power off your battery, under your seat. There are plenty of grommets to get a wire into your battery compartment from the interior of your truck. Since you'll have power all the time, remember to turn off your CB when not in use for extended period of time.
I finished a CB install today on my D90. To make my life easy and keep the wiring under control, I used an Audiopipe power distribution block, attached to the (+) terminal via an Audiopipe positive battery terminal, to hook up my CB power. (I'm also adding lights too.) To learn more about this, see ExpeditionExchange.com under Products.
I agreee with Greg and this is the route I'm going to take as well. darvex.com, the makers of the Audiopipe stuff, have quite a few options for power distribution. I also like thier fused distribution blocks, kills two birds with one stone.
Not the cheapest stuff but that's also a good thing.