There isn't enough room to put this in my comment on your answer, but some years ago the owners of the flats in my block in London nearly chose to change our title to commonhold, but we decided not to and just to give ourselves 999 year leases. I did find out quite a lot about commonhold at the time.
http://en.wikipedia.org/wiki/Commonhold"Commonhold is a system of property ownership in England and Wales. It involves the indefinite freehold tenure of part of a multi-occupancy building (typically a flat) with shared ownership of and responsibility for common areas and services. It has features of the strata title and the condominium systems, which exist in Australia and the United States respectively. It was introduced by the Commonhold and Leasehold Reform Act 2002 as an alternative to leasehold, and was the first new type of legal estate to be introduced in English law since 1925."
I know absolutely nothing about the Australian and US strata title and condominium systems.