I found a company that will make custom RV covers, Trailmanors included.  They have a choice of materials.  I also found a review of this company from the Hi-Lo owners group.  The website for the custom covers is:

http://calmarkinc.com/calmark.htm

The website for the review of this company is:

http://autos.groups.yahoo.com/group/...s/message/1380