Yeah, completely confident they exist. At least I've got some here which strongly suggest they do.
Usb headers on the board are an array of 9 pins, then there's a cable with a block on both ends which goes to a very small pcb with an external usb socket on it. I admit I took this from an old case and cut off the e-sata and firewire ports. I've then screwed it to a spare hole on the side of a hard drive and have usb sticks plugged into it (live cds), so I've basically just moved the front panel connectors into the case where it feels tidier.
USB to sata should be a doddle to find, googling "usb to sata" finds loads. However they do expect an external usb socket, hence the above hacking up of an unloved case. You could instead take a motherboard to front panel cable, hack the end off and solder the appropriate pins directly to the sata adapter but that's a bit brutal for my tastes. The above option would leave a fair mass of cables at the junction, but they can be tucked away in most cases.