This is not really an answer to your question but M-audio produces a cheap USB Audio Interface (24bits 96kHz) called Transit I don't know what chip they are using. You can use this little interface as a start. Red Wine Audio do some mods on this unit to transform it into there USB select unit.
..actually, the PCM2902/6 works also at 96 kHz, also up to 100 kHz. But its bandwidth is limited to 24 kHz. Here are some loopback tests done on a soundcard that I designed, based on the PCM2902/6.
(PCM2902 and PCM2906 are basically the same chip)
The bandwidth is obtained from the FFT of the loopback impulse response.