Woodarchivist.com has an assortment of plans to get an idea. Most things that come from me tend to be based on a plan and I adjust as I need it to. Sometimes intentionally and other times by the wood or custom seconds chances (aka:mistakes that I have to make work).
My recommendation is to find something along the lines of what you envision. Adjust the size or materials to suit the request.
Good luck, sounds like an adventure!
Chris