Although "King Canvas in Seattle area has the patterns and will make camper backs, I believe that for the most part you are best served if you have a local shop make exactly what you want in the way in the way of a camper back. There are features which some like: also the quality of the thread (Gortex or Tenera will last twice as long as Dacron.). You may want a panel which zips out between the top and back of the cabin. You may want panels for the entrance which will zip out. screens in all of the time "U" shaped zip out for the windows. The clear vinyl can come in many different grades which make a difference in visibility and ease of stowing. Some roll up, some are kept flat and hinge up, to be secured under the Bimini. (Those latter will usually have visibility close to clear glass.)
Also the frame, and type of attachment may vary. The cantilevered Bimini has a lot to be said--but it is more expensive.
