On a recent road trip I seen many trucks and trailers equipped with super singles. They are becoming more popular in the trucking industry.
I personally would not put them on a motorhome. I too have many miles rving and never had a flat other than a screw in a tire.
Like I said before if you ever had a flat on the rear at 60 mph it could be quite a ride. Without the other dual to keep that corner up and the lack of clearance on a motorhome the damage could be major. There may be many advantages to super singles and it a choice like everything else.