In 1886 a permit was filled in the US for an invention called "stool and seat" which is a highly deceptive name as it wasn't just your basic stool/seat but a bustle stool. It went over the underlayers but below the petticoats and acted as a part of the structural garments that built up a bustle and included legs and could be sat on without an external chair. You could be your own chair.

Here one can find the permit for it and here one may find it mentioned in the 1887 edition of Scientific American. And if you wish to know about the practical use and how you can make one, Morgan Donner has constructed and tested one here.