no flag. you can't get one. you can, however, register your boat in whatever
state you plan to use it in. your state registration is more or less accepted
in most Carribean countries, except of course you beloved French countries.
There they will fine you for trying to enter without a properly documented
boat.

This is why I am trying to determine under what flag I can register the boat
I intend to buy. I wish to buy the boat then sail it indefinitely. I don't
intend to "import" it anywhere - for a start where too? I am an NZ citizen,
but haven't lived there for 35 years and have no connections there at all
anymore. I currently reside in France, but will have no more connections to
France once I am on the boat. Where do I therefore register to? Country of
birth? Country of last residence? Neither NZ or France would allow that as I
have no address in either country. Or keep the existing registration (which
seems impossible)? Or can I register it under a flag of convenience like
Panama?