I've been designing for about half my life now (started back in middle school and I'm 29 now), so really creating original designs is sort of second nature to me.
As for steampunk Kuroshitsuji, that's awesome. I've thought about doing it myself, but put it off because I want friends to do it with me, but we have so many other costumes we want to make. We have several of us that already do steampunk, so we don't really seem to dwell on steampunking characters because we sometimes want something that isn't steampunk at all. But I wish you luck on your steampunk adventures.