Used boats are usually available at good prices. Buy a couple so you can get on the water NOW and work on your paddling skills. I bought a good, seaworthy boat (a Nordkapp NH) at a price the will allow me to paddle it for a while, yet still sell it for what I paid for it when the time comes. Not only does it provide me with a great boat for "training", but it's also been an excellent testbed for various padding and deck rigging configurations. By the time I get my Outer Island built (at my current pace, that should be some time around '06), I should have my outfitting nailed down, as well as my paddling skills.

One other benefit; it really takes the pressure off and allows you to take your time on the boat(s) you're building, so mistakes are less likely and the final product(s) will be better.