16 Channel Audio

My question is what is the most cost effective way of getting the audio out of a Mac and split to 16 channel (or less prob 5 stereo ch enough)? Would be either from a Mac Mini or if I can get this all ported to a ATV (before it becomes another iOS device!) by someone with the know how, then even better in terms of cost. I'm assuming digital out jack to a break out box is only way to do this. What kind of hardware do people have experience with that's reliable and modest in cost (sound quality isn't really the issue here)?

I'm making a little QC comp to playback multiple audio tracks of spoken word at the same time using Kineme Audio Tools. One track would be instructions in English (goes to a PA) and the other tracks would be same content but in other languages and needs to be routed to headphones. I guess there could be a need of up to 6 languages in any given instance (though in likelihood rarely more than 3). Languages to be played back on a particular day from those available as alternative tracks will be set by admin in some way that the QC comp only has to playback the correct tracks and route them to the correct phone jacks (in some cases multi sends of same language to more than 1 phone jack).

So the 16ch's I see provided in SoundFlowerBed can do it and I have the comp routing to separate channels for each track for any given directory, either in mono or stereo. I'll add external controls probably via a custom box (eg. arduino mc) that can display track info to an LCD as well as playhead control and position etc like an iTunes HUD. The comp/app will also be used to playback video but only in the (single) language on Video file.