I'm not being funny or glib here, but you might honestly be better off finding a center-bath trailer for sale if that's what you want.
Unless you were pretty much planning for a total rebuild, moving the bath is a tremendous amount of work, since you have to move the black tank and possibly the gray, reroute/relocate plumbing and venting, possibly move things like the water heater, etc.
Il Carriaggio — 1975 Argosy 24 | Il Progetto — 1976 Argosy 28 Center Bath | WBCCI# 15566
He has all of the virtues I dislike and none of the vices I admire. — Sir Winston Churchill