I used a carbon/kevlar hybrid cloth on the inside of the hull of my Night Heron. You do have to use some special sheers to cut it and it is harder to work with than plain fiberglass. I think it combines the best of the different properties of both materials. It is expensive stuff but I wanted to use it because: 1) it is stiffer & stronger than straight fiberglass, 2) it looks really cool, and, 3) Nick used it on his Petrel.
"I would consider tackling a Kevlar modification if I needed another kayak.
Fortunately for me I'm well stocked up at the moment. (Whew! Got out of
Pete, you never "need" another kayak but that is a lame excuse not to get another kayak.
The Connyak BBS