My main questions still stand, why the devotion to the main idea that this is housing.  As I said there is no housing shortage right now, prices are dropping, homes are foreclosing, etc.  It seems to me that any community that starts based on this runs the risk of being extremely elitist and primarily those that are rich looking for something novel.  That is not a good base for something that you want to last.  

Here is why I think your theory of dynamic Geography is wrong:

Let us assume that a single residence is the smallest unit.  This seastead must be able to be self sufficient.  That means it must generate its own power for movement, its own food, its own water, it must maintain its integrity as a shelter, it must perform its own maintenance, etc.  All of these things and more it must do to maintain its autonomy, its “freedom of physical association.”

The problem with self sufficiency is that it is not very efficient.  All of these things take resources that could be used in other more efficient ways.  Everything is a trade off, power for food, food for water, etc.  There are so many things to know and do in order to be self sufficient that nothing is done to its full potential, a jack of all trades and an expert at none.  Self sufficiency has traditionally been a subsistence living, meaning the minimum necessary to support life. 

 Now lets move up to the next level, multiple single residences linked together, and the basis of a community.  When you take a group of people and put them together nobody is the same, I mean some work harder, some know more, etc.  So what happens, people begin to specialize in order to improve their lives.  If Sally is better at growing plants then Bob, it makes sense that in this community Sally would begin to take over growing food, she can do this because Bob, who now gets his vegetables from Sally can devote more time to fishing, thus he will catch more fish and provide Sally with fish in exchange for vegetables and so forth and so on.  The end result is that everyone finds their niche because it is more efficient to do so, creating a spider web of supply and demand, interlocked goods and services. 

 As the community grows so do the amount and type of goods and services and again the only way to be good at any thing is to specialize in it.  So say you now have an international banking platform, a food producing platform, a production/manufacturing platform, an energy producing platform.  These platforms would each be specialized because it does not make sense to do it any other way, and now though they may be individual entities they cannot survive without each other.  For example the banking platform, I guess you could distribute the work and whatever computer systems over multiple platforms and if someone did not want to participate they could take their portion of the bank with them, but who would put money in a bank that by its very nature could be here today and gone tomorrow.  Self sufficiency has been lost, meaning autonomy has been lost, meaning that no individual entity can leave without losing what it needs to survive.  Leaving is no longer easy. 

Feel free to tell me I am wrong, or stupid, or misunderstanding what you are saying, but please... please, explain why!