Jeff,
V nice. Inspiring! Love the metal roof thing! This is the kinda stuff that I need to see before the water starts backing up. To date, I had not considered a roof. The wife and I endeavor to stay outta the sun and you have just provided another option (and more work, thank you). The dense woods surrounding our project keeps the humidity high, so I am already nixing an asphalt shingle roof on the future home for fear of uncontrollable moss growth; the zinc strips won't keep up, I fear. A metal roof is almost certain. Now, with your nudge of inspiration, I can foresee a matching roof and roof-line over the dock...and dock-deck.
Question: have you noted any settling? have you made any contingent adjustments available in the event of settling?