How about a real idea?
If you have enough height inside your trailer perhaps consider building a subfloor on top of the existing floor. Sort of like 5th wheel trailers have a "basement" which is where their tanks are put.
Typically most RV tanks are 7 inches or a bit less tall so you could easily make a new floor around 7" higher for the bathroom only or the entire living space. This would also give you a chase for other plumbing and electrical items.
Setup your layout correctly and you could make the tanks go under kitchen or even beds so your raised floor may not need to be the entire living space.
