I claned mine up when I installed the system. Amazing what some carpet will do for looks. Sure the 2 12s have something to do with the "awes" i get, but I think the carpeting is what really makes it look new and clean. I store tools in the compartment on the left, which opens up.
Before
http://images.cardomain.com/member_i...09_28_full.jpg
After
http://images.cardomain.com/member_i...09_21_full.jpg
The kind of odd contours of the 66 trunk would be pretty tricky to carpet...you might want to try and fabricate pieces of plywood or steel to go over the bumpy gas tank and the gaps behind the wheel wells.
Good luck!