Cooltech, LLC, makes an almost invisible 3/8 X 24 mount that fits inside the license plate holder of 2007-2009 Wrangler. They market it as a CB antenna mount, and an 11 meter antenna comes with it... not too sure what to do with that, unless I can de-tune to 10. But it's a pretty neat thing. The only grief is in cutting off a plastic thingy inside the holder, and drilling the correct size hole in the top of the holder. I made mine a tiny bit too big, but clear silicone will take care of it.
It comes prewired with emough RG-58 to reach anywhere in the Jeep, and has a slick little RF conector, factory wired, that fits through little existing holes so you don't have to drill your Jeep. It includes an adapter from the little connector (whatever it is) to a PL-259, but I'm sure you could find one to a BNC for a handheld. I added a heavier ground to the frame, just in case.
Here it is with my 6 meter Hamstick: