Joe,
You're being too specific in your search, and missing it.
Go to the top level and search for 1989 Prevost
You should find two there. This I think is the one you want ...
http://cgi.ebay.com/ebaymotors/PREVO...ZRVsQ5fCampers
Lesson is don't be overly specific when searching, like picking which category it's listed in. It's in Class A Rv's, which may have been where you looked, but it didn't have "motorhome" in it's title or definition.
Ray