For some reason, that url was making your post not show up for me... In case other people can't see it either, here it is quoted, without that link.
One I know of,
Freetown_Christiania, a (somewhat) anarchist 'utopia' claimed as independent from the Danish government in the middle of Copenhagen.
Venezuala has supposedly recognized several enclaves as independent from it, at least partially. I suspect that they are incorporated as local townships. I don't remember the source.
You should check out intentional communities, many of which have that as a goal.
Two directory listings for them are at http://www.ic.org and http://www.icdb.org.
yes, buckminster fuller is quite known, also rem kohlhaas, and also the situationists. an interesting and quite known place for urban utopia are also the russian constructivists.
atlantis would have to be mentioned as an early urban utopia
... and there's actually a film called 'empire me' about 'real utopias' like eg. kristiania.
it's not that good, they say, but it might be at least a listing of interesting places. haven't seen it yet