There is a soft tonneau cover available.
I dunno the specifics ie:water tightness. If it is something like this you can pm AGRIV8R:
http://www.elcovaforums.com/forums/s...21&postcount=2
Also partsguy is selling one you can look into if you are near PA.
http://www.elcovaforums.com/forums/s...ad.php?t=29411
Do a "tonneau" search on the search feature of the forum for other ideas.