I can tell you right off the bat that there will be ASM mixing code. Sorry non-ASM coders. :/ But, this will be mostly to speed up non-OpenAL/DirectSound/EAX, etc mixing functions.

BTW, I managed to coin a copy of the libmodplug C++ library(C compatable) source from a ModPlug XMMS plug-in while I was tinkering with XMMS in Linux. It has full source of the ModPlug loaders and mixers. Something that did not exist publicly until now.

Drop me an email and I'll send it to you. It's rather small. Its code is based off of the ModPlug Sound Engine, but it has been modified since, I'm sure it will be quite a valuable resource for help with OpenMOD