I've tried in the past to work with a whole bunch of people to create new clothing meshes and other items. It seems every time I would take a step forward, I would be set two steps back.
I had went as far as being able to duplicate a clothing item (working in the closet) and retexturing it With nothing more than an image editor, a hex editor, and I think either Urufun, or PRPex. After that I couldn't find anyone to help me, and my life took a turn, so I no longer had the time to pursue it.
I think I still have some of the info on how to do this. It's very complicated and filtered through my words which just makes it worse. However if your interested in how it can be done and possibly translate it to the new tools, which I am mostly unfamiliar with, then PM me.