I have been looking around a lot and the most that I have come up with for this is the fact that we all, those who want to use .obj files for armor have to create our own custom model loader and renderer that will fit into the ModelBiped class. I think that a future release of forge it would be a great idea if we were all able to use the same loader and renderer for our models. This would cut modding time and would allow modders use better modles for armor. I like that you already did this for blocks and items, I think that taking it one more step and allowing armor would be great.
Thanks for your time.