The one caveat on the sledge approach is the following: It there is nothing behind the wedge, then the likeliest reason for its existence is to provide strength, stiffness and support to the pickup bed in lieu of increased steel thickness to reduce overall weight of the pickup.
Think of it as a corner brace you might add diagonally between two boards that meet at 90 degrees; like the metal diagonal brace someone here used to strengthen their camper where the turnbuckle attaches to the camper.
Removal of the wedge might have no immediate impact but may have some unintended result after months or years due to increased flexing of the pickup bed.
Paul
Being a former Manufacturing Engineer having worked on a consulting basis for all of the major U.S. truck makers (Ford, GM & Dodge), I got to know a lot of mechanical design engineers and I got to ask a lot of questions. I continue to remain in contact with many of them.
On the night in Fall, 2010, between visiting ATC on a Friday and the next day when I placed my order, I emailed a friend at Ford.
The answer to what that feature was for...
"That the rear gas tank filler clearance stamped into the bed was for a rear (dual) gas tank. However, the marketing guys reversed an earlier decision and now didn't want to have an option of removing the spare tire, and instead supplying a rear gas tank in that place. BTW, the gas tank was the one being used in the Bronco II. Unfortunately, that marketing reversal decision was made after we had already approved the design and the stampings were created. We were not going to go back and make a new stamping just to remove that feature. There is no structural component to the rear gas tank filler clearance, if there was we would have done the same on the passenger side of the truck bed. So, you are free to pound it out, have fun hammering and camping."
After receiving that reply, I decided to order my Bobcat without the ranger notch in the camper (I did want that space on the inside to be flat) and the day I placed my order Marty drilled the eye bolt locations in my Ranger truck bed and Marty and I pounded out the rear gas tank filler clearance until we were happy.