Just a word of caution I really hate the 16x->16x ribbon style risers ( or ribbon style in general ) I have personally blown the traces right off of them/melted the wires clean off (powered or non-powered both end up the same). Invest in the USB style risers not only do you get more length they are far more reliable.
edit: Jesus dude, resurrecting a 6-month-old post?!
edit: Jesus dude, resurrecting a 6-month-old post?!