Here's one where we got the Dacron for the gaff rig.

West Marine's site has lots of usefull info on parts and pricing.

Here's one that was usefull for the gaff rig design.

Here's one where we got some aluminum bottom bracket shells and seat materials from.

Here's the link where the seat design was inspired from.

Here's a link that had those two links.

Here's a link where we got 1.125" Al tube.

I found Sheldon Browns' bike pages informative.