I'm still waiting for the Mark iv to get off "back ordered" status with Canon, Adorama and B&H...
I doubt it ever will. I bought a used one locally from Craigslist (Actually, it was 285 miles away), it had 1440 shutter actuations and was barely used for $3600. Even the Canon Refurbs cost $4000 plus tax, but are rarely in stock, and then, they sell out in 15 minutes.
I had two to choose from, both with low actuations, original boxes, etc for the same price, I just took the one that was 40 miles closer.
I've seen heavily used ones go for lower prices, but these were almost new.