Snaproll,
Not sure how involved you want to get, but here's something to consider: I have an F-150 with the 6' box and can transport a 35% Extra with the cover that I made for it. Soft tops run $650ish and the "canvas guy" wanted $350 just for the cover (no framing), so I decided to give it a shot. The plane won't fit in the bed with the tailgate closed, so a cap wouldn't work, a regular tonneau cover wouldn't work either because the rudder is too tall, so I had at it! A vinyl tarp, a bunch of snaps, a few pieces of 1/2" conduit, a big old needle, some 30 lb test fishing line (the canvas guys use it so I'm told) 4 or 5 afternoons and for less than $200 I have a top that I can remove in less than 5 minutes. I had it at the field the other day and a guy asked me how much they charged me for it, so I guess it looks pretty good! Works great too, unsnap the back, remove the rear support hoop and roll your plane out, BINGO problem solved!