Physical datahavens only really have meaning if it gets you associated legal services (payment processing, incorp, legal); once banking is fully virtualized, you can do purely online entities too. So yes, datahavens will happen -- they will just be a mix of strongly-associated-with-physical-jurisdiction things, and virtualized things.
The USA is basically a datahaven today for many things, and has been for a while.
slashdot had a bunch of things; I did a Q&A there, and maybe 10 other articles got posted. That, the wikipedia article, and the wired article are probably the best overall information.
Fully virtualized payment processing exists: Bitcoin. In fact, the decentralized and independent currency fits very well the philosophy of micronations like Sealand: https://bitcointalk.org/index.php?topic=8475.0
The USA is basically a datahaven today for many things, and has been for a while.