I hope you find what you are looking for however you mentioned in your reply to me that the diesel will get better fuel mileage.
Diesels get the same as gas units between 7-8 mpg and no better. Now if you are set on diesel go for it and I'm not telling you what to get but since I have been rving since 1989 and have seen all kinds of rv's and talked to all sorts or rv owners I figured I would give you some of my knowledge.
By all means get what you like and I wish you the best of luck with it.
2014 Winnebago Adventurer 35P,Ford F-53, V-10
2011 Ford Escape,2000 Roadmaster Tow Dolly
"Have a Great Day, Enjoy RVing."