Fold a lip lengthwise on some more aluminum rectangles so they have a round exposed edge and staple + overlap them across the ridge. The last cap piece will need caulking on the staples unless you try some tricky folding.
When I posted this Instructable, the roof was in operation for a month with a few spring rain storms. It had no leaks!!!!!!?? Crazy; I wonder how long it'll last.
03 Feb 2009- No major problems so far except for a bad hail storm; it has been about a year out in the weather. I had a few loose staples on the ridge cap last month. See the one-year pictures below. The dent damage seen in the photos was from a golf ball size hail storm late last spring that ruined every roof in town.