You might try contacting some of the hornet control guys in your area and see if they know of any. There is a guy in my area that takes hornets but I don't think he takes the nest; if there is someone in your area doing this kind of work, maybe they could let you know when they get called out to a large nest and then you can see if you can get it. Just a thought.
Maybe Gutpile will have an idea on who to contact?