Well I can think of a buch of original tunes by Great Big Sea that would fit the bill, even they do folk & trad also, perhaps they realy are folk to begin with but I nominate...

"Helmet Head", the loves and travels of a minor leauge hockey player.
"Boston & St Johns" just beautiful
"A Boat Like Giddeon Brown" about generations of a family dreaming of a nice fishing boat
"Barque In The Harbour" about a dalliance in a far off land
"French Perfume" smuggling in New Foundland.

I'm sure there are more from this band.

And I nominate Jefferson Airplain's version of Wooden Ships for everything!