Butcher - exposed timber building is really starting to gain some speed. You may want to try and hook up with some custom builders in your area and see if there is a need and what they require. There are a few problems that present themself with milling big timbers. First of all when green they are freaking heavy, I would think the timbers are going to need to be dried to 14-16% MC, a thick timber can take a long time to get to 14-16% MC air drying (years). I would also expect if you were selling directly to a builder they would want the timbers planed, but maybe they would like the rough cut look too?
Kiln dried furniture grade rough cut lumber is pretty high in demand, most wood workers already have a jointer and planer and are more than happy to machine rough cut lumber in exchange for lower material costs. But there is not much intrest in Green lumber unless it's something unusual or a species that does better with air drying such as walnut. Try and hook up with some local cabinet shops and see if there is a demand there.
You may also want to check some of your local pallet making companies, I know of one in my area that will take all the 4x6-36 green lumber I can supply them and they write a check upon delivery. I've never taken any of my stuff up there myself, but I rode along with a local sawyer freind and was pretty impressed the way it all worked. He basicly supplies them with his low grade cants.
If you can make 2x6 wedges, or crib blocks theres a pretty big market in the coal mining industry. My uncle makes a pretty good living at it and has a reseller that will take all he can supply.
White oak rough cut green fence boards and barn material also sell pretty well.
Some manufactruring companies will buy green rough cut which they make into shipping containers, check around.
If I think of anymore, I'll let you know.
Persoanlly, I think it's just a matter of time and networking, you'll find a nich market.
Thanks