Kip's 41 must have lots of time on his hands...
BUT, if one had the gumption, they could acquire a wiring harness, lay it out on a board and map it, then it would be fairly easy to build them... anyone want to go into business? I've seen this type of board at the USMC Rebuild Depot.. it would be fairly easy to make one; each circuit is mapped to the board, with the wire size and length, connectors ect marked on the board. They have a bunch of nails and it's "follow the little line", bundle them and voila.
look at this web site too.. lots of good info
http://www.madelectrical.com/electrical-tech.shtml