Well, I found a solution for about as close to 100% stealth on a CB antenna install.
I've read about those old antennas that looked just like an OEM FM antenna but were a little longer (for CB's 11 meter band) with a circuit on them which splits off FM/AM from CB. Well, I know they suck. But... I really wanted the mounting hardware so I could take one of those 48 inch CB antennas that do work so I could mount it in the stock location.
I found one at an auction site, new old stock still in the package for about fifteen bucks. It just came in today and the mounting hardware is perfect for a stealth install. It looks like it was made for my Ford. So, I'll use it to mount a modern CB antenna, and a Firestick CB to AM/FM antenna splitter for stealth install without nearly the horrible compromise the "FM antenna which supports CB" had. Instead, I'll have a CB antenna which supports FM. FM will be compromised, but I pretty much listen to AM talk radio and MP3s for music.
Here's a real antenna I plan to use with it: