I ended up adding a tensioner that is bolted to both bars, and it feels extremely sturdy. I got the idea from the thread provided earlier (http://motorbicycling.com/showthread...ight=tensioner
I gave it a test ride today and it held up superbly, but due to my inexperience in balancing the rear wheel, I blew apart my coaster brake and lost all the bearings. BUT, the tensioner held up perfectly, and I'm extremely happy with it.
Thanks for all the advice and suggestions.
Here are some pics: