Is there a good source for those really long arm side mirrors found on the 40s grain trucks? I'm brand new to this decade of GM trucks and am trying to collect information and resources. Thanks in advance for any advice.

Photo references:
http://i215.photobucket.com/albums/cc59/smashsquatch/chevytruck1946.jpg
http://i215.photobucket.com/albums/cc59/smashsquatch/mommens_galen_1946a.jpg