I'm not sure what your question is, but I want to make sure you understand that the Aquaero pin assignment is not a standard MB USB header configuration. On a MB the #1 pin is hot and on the Aquaero the #5 pin is hot. I think a lot of people hook the Aquaero up backwards and I just want to save you some grief.
Edit: Went back and reread your OP. The reason there is nothing on the market is that you can easily buy a single USB cable or make your own double yourself. The Aquaero comes with a single USB cable that is intended to hook up to a MB header.