You should probably talk to the folks at Scamp. Here's what they have posted on their web page:
"FREQUENTLY ASKED QUESTIONS
Q. Can a bathroom be added to a Scamp without a present bathroom?
Can a bathroom be added to a Scamp without a present bathroom?
A. In America anything is possible. But, some things are not easy or necessarily wise to do. When originally building the trailer all trailers requiring bathrooms are laid out for bathrooms before anything else is installed. Water lines are run, wiring is run, and fabric is installed to allow for correct installation of the shower and toilet. This can be difficult to accomplish after the fact. Also, when we started putting in front bathrooms we changed the frame up front to allow for the black water drain from the toilet. Without this frame change the front of the trailer cannot use the present toilet or the
fiberglass shower floor. So, at Scamp we have no instructions on how to add a bathroom and shower after the fact, nor do we do so. There have been several enterprising fellows who have gone to the trouble to do so themselves, so it is possible.
(2/19/2008 7:26:38 AM) "