I actually was trying to get guidance on dealing with Modular homes and Fannie Mae, not a debate on the quality of modular homes, (grunt). It appears after conducting more research that Fannie Mae is ok with completing modular homes on a standard 1004 form. Reference B4-1.4-02: Factory-Built Housing: Modular, Prefabricated, Panelized, or Sectional Housing (04/15/2014). The one line that would cause me to decline a modular home assignment is the statement that says
" When the subject property is modular, prefabricated, panelized, or sectional housing, it is not required that one or more of the comparable sales be the same type of factory-built housing, although using comparable sales of similar types of homes generally enhances the reliability of the appraiser's opinion of value. Fannie Mae requires the appraiser to include in the appraisal report the most appropriate comparable sales data to support his or her opinion of value for the subject property."
My MLS system here in the DMV area which is MRIS does not have a section for modular homes so it would be pretty close to impossible to locate modular homes and confirm if there is a marketing difference between those homes and stick built homes. I do believe this is an essential component in completing an appraisal for a modular home. If anyone that uses MRIS knows a way to find modular homes besides putting keywords (which may or may not yield results because it would rely on the agents stating such in the remarks) please post a reply.