For any OS-X multi-channel audio types: multi-channel audio (now) works for PD (v.37-11) on OS-X for the Motu828 and the Hammerfall Digiface.
Couldn't get PD to see more than the MOTU's 8 first channels: I/O chans 1-8 (analog) are available, but chans 9-16 (ADAT) aren't. Any ideas why?
-Zack