ever thought about a bloodhound or black and tan coon hound? it sounds like they would have plenty of room to run, they bark at evreything that comes on the property and are very freindly. they bark at everyone, but only because they think everyone should have to pet them. also, being failry large hounds they (black and tans especially) can be heard for miles. i know i have been coon hunting and have walked miles to find a dog that i could hear, and thought he was only a few hundred yards away. the black and tans are a less agressive about trying to get out of thier fence, but both can be contained witha little training. they (bloodhound especially) is a pretty big dog, and just the sight of one could ward off anyone you dont want around. both will definatly need a fence, being driven sent hounds means their nose will take them anywhere.
i have a whole lot of experience hunting black and tan coonhounds, and i dont think there is a better hound out there. but bloodhounds are close, which explains alot, b&t's came from bloodhound/foxhound mixes