Backpacks should have their own slot / not take the chest armor slot when equipped, somehow.

Using the slot is easy stuff. The real hardcore stuff happens when I have to render the backpack being actually in your back while being in such inventories.
Currently I'm facing a huge demon trying to solve that with baubles :/

I am very not good with rendering.

It would be nice if you would make it hook into TCon and/or into TravellersGear backpack slot if they are around in a pack. If TCon is around, TG will use TCon's backpack slot. However, I'm not sure if TG has its own backpack slot if TCon isn't around.

Scrapping the baubles and the tinker's construct idea. Going to implement a different solution.

Babules scrapped. Player armor inventory no longer in use. tinker's construct nope.

Special non-slot for the backpack, YES!