As others have stated before me on the forum and the facebook group, the Dodge M400 Chassis motor homes from the 1970s use a 5 on 8 lug pattern like our dodges, Internationals, and Fords of this era, but they are on a tubeless single piece rim. I know that Statesmen is one builder.
I have only seen a couple for sale in my area and always still connected to the RV.
Something that no one has brought up yet, but others have in the past, is the offset for the brake drums having enough clearance for a center rim swap (which I am unsure about)