Howard:

top factors are:

1) efficient cruising speed....to be able to stay with the group
2) light weight
3) good looking

You could consider the Frej or other design from Bjorn Thomasson.
I really like my 16' Frej and you could make one a bit shorter still.
http://www.thomassondesign.com/en/katalog/mina-kajaker/frej
It's surprisingly quick and also handles well.

I don't like small cockpits, so that's one change I made from the design as drawn - Bjorn provides outlines for a small cockpit with suggestions for lengthening. I used my 'standard' cockpit design from a commercial boat - it keeps the sprayskirt collection minimized a bit
I never seem to make very lightweight boats, so I can't comment on the 'lightweight' possibilities for Frej.
By the time I put in hatches and skeg, the lightweight idea seems to be long gone.

i don't mind a build challenge. i have several strips under my belt.

I find the cockpit area transitions to be a bit tricky on Frej. On both builds I was happy that I'd planned to paint, not clear finish over the wood! :-)

Bjorn's Njord is also a very attractive possibility, in my opinion, though I've never paddled one.