I took a cue from AngrySam over at jkowners.com and decided to build a custom bracket to hold my radio where I wanted it, with the bracket reaching existing fasteners (http://www.jkowners.com/forum/showthread.php?t=75601). Unfortunately, I didn't have a any scrap bar-stock, laying around, nor do I have a welder in my garage. I was also on a budget. That meant that I would need to build with affordable materials that are easy to work with. So the wife & I headed off to Lowes.
We picked up a couple of Galvenized steel struss straps, and some small machine screws.
After returning home, I removed the front mounting bolt for the front passenger seat. I then bent one of the truss straps to conform to the curve of the Jeep tub to bring the end of it to roughly where I would want the radio. I marked the radio bracket and the end of the strap to drill a couple of corresponding holes & attached the 2 together with the machine screws. Then, I drilled out the other end of the truss strap to have a hole big enough to allow the seat bolt to pass through, and attached the whole thing through the seat mount. I found that this wasn't as secure as I'd like and the whole thing tended to wiggle.
After searching around, I located a second mount point just below the dash, under the carpet. I took a second truss strap, bent and trimmed it to match that bolt's mounting bracket, and to end at the same point on the CB bracket. After drilling holes in the truss strap to match the previous attachment, I screwed the whole thing back together and re mounted in the Jeep, using 2 mounting points to secure it. This time around it would barely wiggle. Tossed some industrial Velco on the back of the bracket covering the screw ends, and VOILA! Unfortunately, I didn't grab any pictures of the bending of the second strap, but I'm sure you all can figure it out ;)
Not including the Lowes run, the whole thing took about an hour, maybe a bit more with stopping to take pics for this write-up, and undoing everything to correct the bounce without the 2nd strap. Not including gas, the whole project cost less than $10.