A lot would depend on how large of a mh you want. If you want a larger more luxurious mh then it is going to weigh much more and require a diesel to push it. There is a big limit to how heavy a gasoline powered MH can be. You say that it is more money to maintain a diesel. I can bet you that when you gasoline motor is worn out and requires rebuilding that my diesel is still going strong. Same goes for the Allison transmission. If you are going to keep the mh for a long time and put many miles on it then you also have to take that into consideration.
"Gunner" USN Retired, Airdale
2004 Monaco Signature 44' Conquest. Detroit 60