AIRE has a great reputation
Posted by: TetonJohn on Sep-14-12 11:42 PM (EST)
for inflatable boats, including kayaks. Although they mostly make serious whitewater kayaks, they have some that would be better on flat water or both flat and white.
In the Tributary group, under Touring, see the Sawtooth. Also, see the Strike.
Another good website is:
Some folks here will likely suggest folding kayaks -- which I know nothing about, but which may work for you.