On my rig, I've got an ADA8000 to do pretty much the same thing you're talking about. Mine feeds my headphone mixes to my distributor so that I don't waste my good channels of conversion on BS. I also use it as my other 8 channels after my Germaniums, and to tell you the truth... they don't sound bad at all.
If you want some proof, check out this band I just finished up. I took the Snare and the Side of a midside through my Germs, but everything else on the kit is through the ADA8000.
http://www.suburbanprostudios.com/muzak/Pack It Up.mp3