When I first bought my truck a member of one of the Diesel sites was selling end cap oil filter wrenches machined from billet. They fit the fleetgaurd filters and had a 3/8 drive square in the end.
I tried to purchase one but he was sold out and was not making them any more.
I have one made from plastic but it easily slips and most times you have to fight with it while trying to remove the filter.
I would be interested in one if they could be made.
I like this idea as well as the Door sill covers for the QC, they should be easy to make.