XK-AUDIO-216-MC free GPIO pins?

[infiniteimprobability]

Other options:

You can use SPDIF/ADAT tx to get 2 x 1b ports - the signals are brought out to PTHs marked C_TX and O_TX. You'll get a copy of your signal on the TOSLINK/COAX pins but that's not an issue..

I have also frankenstiened boards in the past by soldering wires onto the LEDs. You can get whole 8b port (or 2 x 4b) this way..