and tabard geometry are part of the base character model. You can't make them separate patches and be interchangable because they would override the same files.
If this is the case then, if possible, please make a (normal?) version without the new tabard as well. I really like the WoW-standard tabard, it moves so nicely back and forth while running.
But please don't misunderstand, I however love the details you've done between the legs in the new version. Very nice eyecandy at those times while not wearing a tabard.