A sister of a friend of mine owns a small company called Second Wind Sails. She's been been making things out of old sails for at least a few years now, and makes a whole variety of bags. She also makes a messenger bag! If you know something about sails, then you know it is incredibly durable, water proof, and tough.
When I receive mine, i'll post pics and give a review. I already like the fact they are made of a material that would normally be discarded. From what I understand (which is very little) sails need to retain a certain shape when full of wind, and if this shape isn't right for a certain racer, or a certain crew, another sail is used and the "bad" sail is discarded. This is a very simple explaination, so if you know a sailor they can explain more. She does custom images as well.
Stay tuned if your interested.