Skippy actually has plenty of ponds that are larger. And, yes, he swears by NEVER cleaning the bio filters out. Claims that when he did clean one out (eons ago), it created a problem and has never done that again. Skippy will tell you that pond size will have nothing to do with it--whether small or huge. He replicates his system for any size.
You can read about it here:
http://www.skippysstuff.com/ and you can even call them up and chat with them. But yes, the claim is that they create their bio filters and never EVER touch them.
Of course, Pondjunky, to do this you have to maintain pristine water conditions, have the optimal number of fish, feed them appropriately, do meticulous water changes, etc. And reality is that most folks don't adhere to any of that. They overpopulate their ponds, do weak maintenance, etc. So, if you can live by Skippy's rules, you may just have his success, too.