Ditto on Marathon. Mine arrived and upon installation i noticed that the optional headrest covers I had ordered were missing. I called them and the owner answered,apologized profusely for the omission,and shipped them promptly. i do wish I'd selected a camo pattern. Be sure and order the front and back pockets.I don't have a megacab - but I have a set from Marathon ( marathonseatcovers.com ) for both front & rear seats (console included).
Absolutely love them - got the eastern hardwoods camo pattern in 500D Codura. Took about 2 hours to get everything on and the fit was perfect. Holes for power seats, lever and knobs, etc.
They are expensive ( $525 for my whole set ) but their customer service is second to none. Once you order they call and confirm every detail - mine also were shipped fairly quickly.
I do concrete construction for a living and so far (6 months) they are holding up great.
Anyway they get my vote - and I'm sure the fit would be excellent for your megacab.:thumbsup
i have these seat covers also and love them!