My first choice might be to go to one of the smaller. older places where it is more like and individual sorting through things as they tend to have some old stock at times. NOT a Camping World, etc but one of the out of the way places, if there are some in your area. Then if no luck calling looking around from those, I would get out the phone and start calling some of the Winnebago places around the country.
2015 Winnebago Vista 31KE on 2014 chassis