alot of junkyards have them around here (Park Rapids area). "Jepson's Autobody" is a good one and near fargo there is a huge junkyard that primarly has classic fords and chevys, but im not sure what it is called off hand.
Check out Joe's Ford parts in Vermillion, MN. HWY 52 south out of St. Paul, take 190th toward Vermillion and go through town. The wrecking yard is on the left up on a hill. He only deals in Ford parts. I hope this helps you.
Here is some more info for you regarding local parts suppliers.
Joe's is open Mon-Fri 8-12 and 1:30-5; and on Sat morning from 8-noon. The phone # is 651-437-6787 at his shop. The actual address is 5849 190th St. E., Hastings, MN 55033. If he has what you need, UPS service is available.(Not for an entire bed I'm sure.)
Just FYI I went by Little Dearborn Antique Ford Parts located at 2424 University Ave, MPLS this morning and gee, they're only open Mon-Fri also. It sure makes it hard for customers to do business with stores that are not open when you have the opportunity to shop there. They do not have a catalog on-line yet for trucks. :-(