Rhode Island Wire is a good source for original cloth covered wire and vintage terminals.
http://www.riwire.com/. Another is YNZ Yesterdays Parts.
http://www.ynzyesterdaysparts.com/. These suppliers can do the entire harness or you can get just the wire and termimals and do your own thing with vintage looking wire. I liked the link for Magnetoparts.com, it's got good stuff too, thanks.