I want to make a tonneau. What recommendations for the best material that can be machined up on a domestic sewing m/c. It will only be used as a protective cover but it needs to be water proof.

I've used this stuff for my soft-top

http://cgi.ebay.co.uk/Black-fine-Ottoman-rib-waterproof-fabric_W0QQitemZ120040721919QQihZ002QQcategoryZ83926QQrdZ1QQssPageNameZWD1VQQcmdZViewItem />
Medium weight. Waterproof, easy to work with, not too thick... Good stuff... and the price is right... Looks quite classic (like normal soft-tops).

For weight though you could go for just a plain tarp type material.