Sadly, the wavelength of CB means that a decent antenna has got to be at least 9 feet long, electrically. Add to that that it should be in clear air, above everything else, and you've got a recipe for clearance problems.
Consequently, pretty much any CB antenna is a compromise. For what you want, though, I imagine one of those mag-mount ones would be sufficient. Keep in mind that most of the roof is covered in ridges, which sort of limits where you can put a mag-mount.
Also, you're pretty much guaranteed to scratch your paint with a magmount.
A couple of people have done permanent installs to the tailgate door, in installations that look pretty good. I think they're probably the best. There are others that will fit in the trailer hitch, if you're got one of those.
I drilled my roof, but then the antennas I use are only 19" long, and aren't any higher than the stock antenna. Hit up the search engine for other installs.