If you don't need an OEM-duplicate harness, look at American Autowire.
Used one of theirs on a customer's old Ford truck, and was real happy with it. I converted 6V/+Ground to 12V/-Ground with an Alternator. I bought it through Summit.
They do have some plug & play harnesses, but they were Chevy/Ford stuff last time I looked.
I'll use them again on an LS/FJ40 swap coming up.