Here is another option. I have an FMC which is 29ft. They came with Chrysler 440's so they were gas pushers. They were built from 1973-76. Over the years a number of them have been converted to diesel engines. To do the conversion like I did is a large project. I am not recommending that. Periodically, units that were converted at some point in the past come up for sale.
The key is the quality of the conversion. Recently, a very nice one traded at about $16,000.
If you have any interest send me a PM and we can discuss the possibilities. You are in Clayton, CA and I will be in your area in Feb if you want to look at mine. There are others in the greater bay area that you could go look at to see if the coach fits your needs or not. They have independent rear suspension so the wheel base issue does not exist.