@ tclederman, Look at John's picture, that's it!
@ HRJ, Thanks, John, that's it. I've never seen one in a fleetside, though. What a cool mod for a pickup. It is looking more and more like I'll have to build what I want anyway. I think the easy way to go would probably be to start with a trailer fender that fits the biggest tire you might need.
Thanks for the input!
Les