I read long and interesting posts about reunifying Roman Catholics, the Orthodox, and some high church Protestants. I am not sure that I can address some of the specific points with much clarity, but I can see where a significant change in Church heirarchy could facilitate unity. Of course, I don't think change for change sake is good for anything, so we must have some tradition or some biblical basis for doing what we do. This is why I'd like to propose, in the most abstract sort of way, the Matthias Option.
It rests on Acts 1:12-26. The twelve apostles had just recently lost one of their number. Apparently, they felt it extremely important to fill the postion that Judas had held; it fell to Matthias. Just as the bible provides us with evidence of Peter's primacy (from the mouth of Christ no less), so to do we have an indication that the 12, as an entity were important.
So, what does this mean? Well geography becomes less important. The Pope's primacy becomes much less scary to the other Churches because the Vatican bureacracy becomes far weaker. We have the more well known Orthodox patriarchs who would obviously be part of the twelve. I'm sure certain choices would be contested, but it shouldn't be a deck stacking exercise.
America, in particular, presents the most interesting case for a unified Church. We have several Catholic Churches, a couple Anglican Churches, and at least two Orthodox Churches in my hometown. After the dreamed of unification, how do jurisdictional issues get hammered out? When we have at least four bishops?
I suggest that without something like the twelve, we'd end up with a situation currently experienced by the Orthodox in this country. They are in communion on a sacramental level, but they are divided on an administrative (and often ethnic) level. Now, this doesn't necessarily mean we have too many bishops- I have been thinking for a while that we have allowed our churches to grow too large; often there are not enough clergy to do the proper pastoral care, and smaller dioceses would be a step in the right direction.