Modeled a naive approach to making a rail to fix hinges onto.
Not quite sure whether this'll work in the real world, tho…
I have the creeping suspicion that the pipe will just deform along the cut, because it goes all the way through (so you can actually slide the hinges in).
But I'll have to model the complete skeleton before I can begin properly estimating the weight the hinges have to bear, so I'm not worrying about that for now. :P