My suggestion is to take a look at what Current Designs has to offer. They seem to do a good job with poly. I would also recommend taking a look at What Necky and Old Town have. One of my boats is an Old Town 138 Loon and for the kind of paddling you're talking about, it would be superb. It doesn't come up to the 14' you mentioned, and it is kind of heavy, but the Loon is a great boat. I don't think they build them anymore, but you might find a used one.