Jason...the only other thing i can think of are the HRT Musicstreamer USB DACs which support 24/96 digital formats but they are standalone DACs not converters and they got solid reviews (http://www.musicstreamer.co.nz/).
My sense was that you wanted to use a USB to S/PDIF converter to use with an existing DAC. Here is a resource that might be useful: http://thewelltemperedcomputer.com/HW/USB_DAC.htm
The other resource that might be useful are the forums at the Computer Audiophile website: http://www.computeraudiophile.com/
Hope this helps Jason. Good luck with your search.
My sense was that you wanted to use a USB to S/PDIF converter to use with an existing DAC. Here is a resource that might be useful: http://thewelltemperedcomputer.com/HW/USB_DAC.htm
The other resource that might be useful are the forums at the Computer Audiophile website: http://www.computeraudiophile.com/
Hope this helps Jason. Good luck with your search.