Review mar-k bed wood finish experiments. Good info about what treatments hold up
I did right after seeing your response and was amazed at how the painted boards looked in the 2010 wood test update. Definitely going with paint, and painted as Tim (tclederman) and Mar-K says to. Unfortunately my truck sits outside 24/7/365, so the finish needs to be durable for when the camper shell isn't on the back. When I haul material from the bulk yard I'll make sure to put some plywood on top so the shovel doesn't scratch the finish as I get to the bottom of the pile.