Bringing one back from the dead here...
Did you ever end up replacing your headliner? I have the thin fabric style which I would like to replace with something more appealing and was curious what you ended up with. Would appreciate any pics, install tips, ect... I haven't looked at it for a few months, but I seem to remember it looking like a real b*tch to dissemble around the outer edges?
I found some non-woven material on close out and bought the whole bolt of fabric. It wasn't wide enough to cover the whole width, so there is a seam under one of the 'boards'. Speaking of the boards, I did use the plastic covered closed cell foam; bad, bad move. I need to replace all that crap with pine screen mold or something because the staples tended to blow the foam to pieces.
I just took a sharp knife and cut the old material off right at the edge of the outermost framing members. I threw all the fiberglass insulation away and eliminated the electrical splices that were hidden inside the ceiling. (Note to fabricators: If it's not allowed by the NEC, why do it in the camper?) I reinstalled one inch thick rigid foam, which I cut to squish-fit between the framing members.
The main reason I did this was not to replace the liner material, but to try to find some vexing leaks in my camper. I found one: There were a couple hairline cracks in the plastic mounting flange of my vent fan. I fixed these ant that leak stopped. The other leak was not so straightforward.
I had long felt that the camper seemed to leak more with the top down than up, and it leaked badly in the cab-over on the driver's side. My cushions, ceiling and soft-side material were mildewed in this area. I decided, after removing, inspecting, re-caulking and hand torquing all the screws in the roof and the edge banding that I would strip the ceiling and observe what happened for an hour or so during a typical Texas gully-washer. I waited in vain- not a single drop of water cam through the aluminum roof skin, nor any from around the vent either.
I had already done the P-gasket mod around the front third of the camper, so I figured the water wasn't coming through the folded soft-sides, but i was wrong. Apparently, the way the truck sat in my sloped driveway, the rain was shedding off the roof slowly enough that it followed the driver's side edge-banding from back to front, running inside the P-gasket, inside the folded soft side, through three layers Velcro'd window flaps a onto the cushion, where it evaporated and re-condensed on the ceiling material as well. I surmised this after I found water inside the cab over when the top was down. The confirming experiment was to caulk a piece of white plastic screen-mold to the entire driver's side top edge of the camper. This forced the rain to shed entirely at the driver's side front corner of the camper, and the cab-over area has been dry ever since. I think this insidious problem might have occured at any corner of the camper, btw, depending on which way it sloped while parked.
I am behind several reports on mods I've done. I have been motivated to do 'em, but not motivated enough to report 'em. Sorry for not holding up my end of the deal 'round 'ere. I'll see if I can do better in 2011.