The Antenna: Variation's on a theme
My initial attempt at creating a ground plane antenna was so successful that I left it alone for quite a while.  After seeing pictures of how other people implemented my antenna, I decided to do a little more experimentation.  My goal was to maintain or enhance the capabilities of the antenna, while at the same time making it more sturdy, and maybe a little bit easier to build. 
Antenna considerations and options
So much of what has been successful with my antenna has been dumb luck.  I continue to tweak and fly, tweak and fly, and hopefully end up with something better.  If there are any antenna designers out there cringing at the work I'm doing here, please send me an email, let me know what I'm doing right, what I'm doing wrong, and what I might be able to do better.  Thanks, Bill
Construction Details
 My new antenna leverages off of a lot of the work I did on the first ground plane antenna.  It all starts with a small square of pcb board cut out of the original XCam2's patch antenna.  The primary difference is that the hole in the middle of the board only has to be big enough to thread the internal coax insulation.  To determine the size of the hole, read on...
The most significant design change I made to my antenna was to replace the coax cable that came with the XCam2.  After repeated experiments, my original cable was getting thrashed, so I needed a replacement.  I selected RG174/U, available from Hosfelt Electronics for $.19 per foot.  In this picture I've already prepped the coax by stripping 5cm of the outer sheath, cutting the braided shield down to about 6 mm, and tinning the shield.  The exposed signal wire will act as the main radiating element.
A couple of things have occurred in this picture.  First, the pcb board has been threaded over the signal wire and is resting on the top of the tinned coax shield, with the copper side down.  Second, the pcb board was firmly soldered to the coax shield from the underside.  Third, the four ground wires were soldered to the pcb board in a pin wheel pattern.  This is shown better in the next picture.
Here is a detail shot of the four ground wires as they are soldered onto the base of the antenna.  By soldering then in a pin wheel pattern, I was able to get more of the wires in contact with the pcb board, thereby giving me a stronger solder joint.
This is the final antenna shape.  The four outer wires are bent down at a 45 degree angle from their former position, and cut to exactly 3cm in length, measured from the bend.  The signal wire is also cut to 3cm, measured from where the signal wire exits the coax shield. There is no additional support for the signal wire since I wanted it to have a little bit of "give" in case of an accident (I've bent more signal wires while handling the plane than I have while flying). 

This antenna gives an approximate 15 degree up-slope to it's coverage area, so it will give good coverage when mounted pointing down on the airplane.
That completes the construction of the revised ground plane antenna!