Here is a link listing authors and books about those style of trucks. Maybe your local library or historical society can help you get some more info. Also, contact the folks at Vintage Truck Magazine published by Patrick Ertel. They recently published a series of articles on "Delivery Designs" although I couldn't locate a "Metropolitan Body" article. Perhaps even a letter to the editor with a pic will help you.
www.vintagetruckmagazine.com
[email protected] for a letter to Pat.

http://www.coachbuilt.com/bui/m/metropolitan/metropolitan.htm

Was your grandfather this Buchan? See article.

http://www.buchanbakers.com/gpage13.html

Last edited by DrewP; 11/07/2009 3:03 PM.
Drew