Look at the Truxedo Truxport tonneau. The Truxport is a roll up top mount on bed rails and cost $250 from four wheel on line .com.
The Truxport is a cheaper version of the Truxedo. I don`t know how great a cover you want? For my money this was the best deal I could find. I couldn`t see paying 400+ for a soft tonneau cover.
I have had mine since spring and like it so far. It looks good but I`ve seen nicer covers, not at this price though.
http://4wheelonline.com/Images/Categ...portRolled.jpg
http://www.4wheelonline.com/