If you check out the Geodesic Airolite method of constructing SOF boats you'll see that he reinforces them with kevlar strands. (www.gaboats.com)

Kevlar fabric used for a reinforcement with plastic resins my be a more-open weave so it can wet out easily, but kevlar fabric with a tighter weave is made. It is used for making bullet-proof vests for police and military. Cut-proof garments are also made for loggers who work with chain saws. Frayed Kevlar brings a chain saw to a grinding halt in a hurry.
The closer-weave fabric may be available as military surplus, or an odd lot might show up.
Loose weave Kevlar can be coated with a trowel-grade elastomeric roofing/patching material. Do this before you try to skin a boat with the stuff. If the inside is coated with such a material, then the outside can be coated with something else. The abrasion resistance of the fabric would prevent a scratch on the outside from turning into a leak.

If the fabric doesn't stretch you'll need to do some creative tailoring. Think darts, multiple seams, and a bit more coating to seal all the stitch holes. By first coating at least one side of the fabric while it is flat, your seal coat will bind the threads of the fabric, preventing unraveling.

PGJ