Suggestions/recommendations for motorhome cover

With what you are asking for I would suspect you will need to have the cover custom made. When we decided to have a Kilt manufactured (I wouldn't put a skirt on my "handsome" 40 foot 5er) Hired a company out of Boise, ID with a mobile tech who drove up to SE Washington and he spent two solid days in the winter cold manufacturing and fitting the custom Kilt. Made a big difference in temps under the 5'er. Within 20 mins the airspace under the trailer was 10 degs warmer then the outside temp.