@spirantho
I doubt it is a full digital path for SPDIF, as the chip seems to provide only analog outputs. Unless you are doing something wicked with that built-in XilinX.
On the hardware side, you could offer something interesting with the 12 GPIO pins the DSP chip has. Maybe an expansion module that could provide a sort of Geekport or a simple series of relais for controlling fun stuff, or even a LCD module that could display some playback parameters.