Man that is one fantastic rat rod. Love the roof structure rails, great work. I like how you did the step in the interior, no messing around with awkward floor board configurations.
Nice detail work, the colour scheme and graphics works well on it. I've never been a fan of the Createx paints. Have you tried their line of AutoAir, Wicked or their Illistrator paints?
Great experiment, they both look to be exicuted really well. I think they would work, of course as you said the paint will tell the true story. I really like the n scale stair idea, might have to borrow that some day.