Does anyone know about a usb 3.0 internal header to usb 2.0 internal header
USB 3.0 is backwards compatible but you cannot say, plug a front panel usb 2.0 header into a boards USB 3.0 header or vice versa. Not only is the header for USB 3.0 bigger, but there are extra pins and the layout is flipped so nobody makes the mistake of plugging one into the other.
$75 SIIG SuperSpeed USB 3.0 Bay Hub+Host Kit Model JU-H40411-S1 -> http://www.newegg.com/Product/Product.aspx?Item=N82E16815150170 ; problem the bandwidth via the HUB is split across the 4 ports @ {Front Panel} but also offers a rear USB 3.0 that is not shared.