I don't know if you'd be interested in doing it this way, but here's mine-
http://s660.photobucket.com/albums/uu326/Old64Suburban/ I insulated n soundproofed between the ribs, screwed 1X3s to the ribs longwise(5), and after spray gluing the ceiling material to some 1/4 Masonite I'd cut to fit, I then contact cemented the panels to the 1X3s. It took 3 pieces, leaving 2 seams across. For these, I wrapped screen molding with the material, and used a brad nailer to attach these over the seams. You have to look for the nail marks to find them. I believe a pin nailer would be even less conspicuous, but you'd want to nail at a little bit of an angle, since they have no heads.
