I like the bedliner idea. I would do that, but wouldn't try to match the color. Just go with grey or black.
As to the oil, I think the conventional stuff is just fine, and you shouldn't be able to take advantage of the longevity as your oil will get too dirty. The 15-40 stuff is supposed to be getting reformulated to take out the ash/phosphate (yay!) since the new ulsd fuel is not as acid, but also taking out the zinc which is a SIGNIFICANT wear inhibitor (boo!) due to incompatibility with common rail catalytic converters.
I will probably be switching to straight 40 wt to keep the zinc. I have rebuilt a significant number of engines, and have seen pre zinc engines and post zinc engines, and have yet to see a post zinc engine with a cylinder ridge (even one that smoked a crank/rod from NO OIL till it siezed). 'Course it wouldn't be the first time I was called a crackpot, but you can verify this information fairly easily.