I don't know if this will be of much help now but I just bought one of these as it seems to be a better deal than buying just a harness. I found a harness for $105+shipping (in Seattle I think) and then I found a factory hitch and harness on ebay here for $129+shipping.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260372827838&sspagename=STRK%3AMEWNX%3AIT&viewitem= I paid $132 for my aftermarked hitch and wish I saw this before buying just the hitch a while back.