I'm doing some body work on my Bittle and wanted to reshape the legs, but recreating the mechanism is complex, and I did not have alternative servo horns that fit. So I made a clip that snaps tightly onto the existing legs, that can be used as a base for new leg designs, or just to glue something on to.
I based it on the official thigh .stl file, and it fit like a charm on the first try (though the cables can be a bit fiddly). I hope people can use this. Feel free to add it to the github repository.
Hopefully it won't interfere with leg movements.