BusinessWire reports that the Dublin-based Research and Markets firm has added manufactured housing (MH) to the list of industries included in its reports.  The article says the $3 billion MH industry comprises 200 companies, but is dominated by eight firms accounting for 60 percent of revenue.  Four of the largest are Cavco, Champion Homes, Clayton Homes, and Palm Harbor Homes. While manufactured homes are built with chassis, they are not made to move often, but the report does not include prefabricated buildings without a chassis.  Manufactured housing accounts for over 90 percent of the industry revenue, with the remaining being nonresidential building such as offices and classrooms. Demand depends upon availability of credit as well as other housing options.  The report says most of the manufactured housing sold is multi-section.