Portland would be great for James from a strictly basketball perspective but like San Antonio I just don't see him going there (though San An is more likely), but for the sake of argument would the Cavs do something like this and in that i just don't know.
Cleveland - Turner, Collins, Harkless, Swanigan, Aminu, and a couple of 1sts
Portland - James, Smith
Portland also has a trade exception large enough for Clarkson which could be an additional incentive for the Cavs.
So the Cavs would unload Smith and Clarkson, get some young players and some draft picks (tjough do have to take on Turner and Harkless). The Blazers would be filthy with James, Lillard, McCollom and Nurkic (though would be way into the luxury tax)