Get a few of these hitch rings:
with 2 thick 3/8" fender washers, and 2 locking nuts...
then sandwhich it as follows:
Locking Nut | Fender Washer | Hole | Fender Washer | Locking Nut | Hitch Loop
And you got yourself some fantastic tie down's in the 4 corners of your bed
Edit: And yes I just made it up in my head.. and I might do this in my own truck now.. seems like a damn good idea to me!