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.
http://www.aire.com/aire/products/default.aspx?type=33
In the Tributary group, under Touring, see the Sawtooth. Also, see the Strike.
Another good website is:
http://theboatpeople.com/inflatable-kayaks-canoes/
Some folks here will likely suggest folding kayaks -- which I know nothing about, but which may work for you.