I think 4crawler has a writeup about how to do a CB antenna where the stock antenna is.
I would avoid magnet mounts - no matter where you put them, they are ALWAYS getting knocked off. Mine is on the rear exo, but you could use one of the trunk mount brackets and do it in the similar place attaching to the tailgate.
The Wilson whip antennas are AWESOME, but pricey.
I've broken two Wilson fiberglass antennas and recently changed to a stainless center load "Hustler" - something like this:
I am sure I would have broke another fiberglass yesterday, and this one held up GREAT! Can't report on it's reception and stuff yet as I haven't got the SWR tuned in on it yet.