MacGyver'd it
This afternoon I went to Lowes to check out their 2 aisles of hardware. I found some poly coated chain that I liked - they had three different versions of it - green, white and yellow. It's only $0.54 per foot and it'll handle about 250 pounds (I forget the exact number) but since we're not lifting with this chain that should be plenty.
I didn't measure the distance between the tie down loops so I winged it and bought two 7' lengths for the sides and a 6' length for across the front. I knew that'd be more than enough and I was right.
I also purchased four connectors that are a single loop with and straight section that unscrews open and screws closed (securely). It too has plenty of strength for the job.
Installation was about 5 minutes. You can see all the extra chain. I'm going to leave it (in the two front corners) because it might actually come in handy to have additional play in the chain as it could make it easier to use.
I plan on using bungees and tie-down straps by connecting them to the chain. I'll also use the web cargo net I have. I'll let you know how well it works. Right now it looks like a good solution that is made better by the low cost - about $15 (estimated).
Here's the connecting link attached to the tie-down loop with two lengths of white chain attached to it:
Pic of right rear tie-down loop near the tailgate behind the Bed Extender:
You can see the right side of the bed with the chain running from the tie-down loop on the right near the tailgate (behind the Bed Extender in my Raptor) up over the wheel well up to the right front tie-down loop. You can also see the extra length of chain:
Close up of the connector: