i have always wanted to cut a metal top off and make it removable too, i though about using the in half of the window trim and weld it to the top. cut a 0* over the windsheild and under the rear window and weld in flats with a 1/2" x 1/2" bar to locate and seal with a 1/2" channel in the top.
here is one that came up this morning
http://www.67-72chevytrucks.com/vboa...d.php?t=210381