I'm against killing of wild or endangered animals to make articles of clothing, but I figure if the animal is being killed for food, then it is fine to use as much as possible (not sure about the whole mounting of heads on the wall thing though). As far as I know, no one hunts elephant for food, but they are killed for people wanting a piece of nature, as it were. It's hard to argue that it's not a shame that an endangered species is being further threatened by people wanting especially supple purses, pants, studded suspenders etc.
To add to your list, I know of a buffalo farm, as well as an ostrich farm, so those can be considered farmed animals too. Of course, this assumes that the animal is being farmed for food and the skins are used for other purposes and therefore excludes most fur-farms that breed the animal for skinning only.
It's a fine line, and someone will have a wise-ass remark about pet goldfish, koala bears or something equally ridiculous making great straps to annoy those of us that care about such things, but everyone's entitled to their own opinion I guess, even if it's wrong