Thanks, SD. I've tried the furring strip thing, and it worked, but looked fairly amateurish. I stapled the padding and the vinyl to the furring strips, and then tried to screw finished furring strips to that to cover the staples. It's up there, and I'll probably leave it there out of laziness.
When you are feeling energetic again, take out the stuff that you attached to the furring strips. Finish the furring strips with a little sanding and urethane/varnish/whatever.
Take some large pieces of brown paper and make patterns for panels to cover the spaces between the furring strips, leaving a little space between each panel, so that the nice job you just did on your strips can be seen by everyone.
Using the patterns you made from the brown paper, cut the panels out of thin plywood, or that plastic that is constructed like corrugated carboard, or anything that is thin and fairly flexible. Don't destroy the paper patterns when you are finished, as you will use them later.
Choose something that you want to use for your headliner and lay your panels on top of this. Cut your headliner material or vinyl or whatever about 1 1/2 inches larger than your panels. i.e.: You want a 1 1/2 inch allowance on all sides.
Take the panels off the headliner pieces that you have cut and, being careful to make sure that you are spraying the correct side of them, spray the panels with some type of adhesive that will not work its way through the headliner material.
Now lay the panels on top of the material lightly and adjust to make sure that your margin is relatively even everywhere and that there are no wrinkles or folds anywhere.
Next, take the paper patterns that you made and lay them on top of the covered panels to make sure that things are still the size and shape that they should be. If you are using a thick material for your headliner, you might need to shave a little off the perimeter of the panels as you want them to be the same size as you patterns when you have completed the next step, which is...
Fold the margin over the panel and glue it down securely. It is easiest to do this if you glue one end first and let it dry, then glue the opposite end, and when they are both dry, glue down the sides. This will give you a wrinkle free job.
Now take the paper patterns that you made and lay them on top of the covered panels to make sure that everything is the size it should be. If it is, mark holes for screws on the paper patterns. Depending on the amount of camber in your deckhead, you may need to put screws every 6 or 8 inches, but if it is fairly flat, then every 12 to 15 inches should be good.
Take some time to measure this to make sure that you are ending up with an even set of fasteners, as it will make a big difference in the final look of your boat.
Now mark these holes on you headliner panels and then determine what size screws you are going to use. Note that you can finish your screw heads off two ways - you can buy screws that will take the little plastic caps, or you can get the stainless finishing grommets that go under the head of the screw. (If you decide to go with the caps, make sure that you can get them in your area - apparently they can be hard to find).
Next, before you make your holes, take some adhesive and a Q-tip and put a dab just a little larger than the diameter of the screw, on each of the marks you made on the headliner. Let it dry.
Get a hole punch that is the same size as, or slightly larger than you screws. Use the hole punch lightly, to cut a clean hole through the headliner material. There should still be a tiny little magin of glued down fabric around the hole. Don't worry about getting it through the panel itself. The reason for doing this is that if you try to drill through the fabric with a drill bit, there is a very good chance that the fabric will get caught in the drill and tear, twist or rip (See my brother for details
Now drill your holes through the panel, hold the panels up on the furring strips, mark the hole locations there and drill little pilot holes.
Finally, attach your headliner panels, have several beers and call all your firends to come look at your beautiful cabin.