Cities in space - Singles or clusters?

Greetings list-members,

All the talk about how things would be paid for in space and what kind of
currency would be used got me to thinking, now I know that this question has
probably come up before but maybe we can look at it from a different angle,
so I have a hypothetical.

First, let me arrange the setting, the time is the future, maybe a hundred
years or even a thousand years from now, assuming they have a tame
worm-hole, star trek transporters, super cheap spaceships that can be used
like the family car with a dollar per tonne costs, anti-gravity devices,
some new kind of physics or even magic pixie dust but getting to orbit is no
harder than catching a train or bus from Canberra to Sydney (hey, I am in
Australia :), people got a dose of the smarts (or the laws stopped the
terraformers) and other than small outposts on the planets/moon and the odd
diehard Mars or nothing, all the space colonies are orbital, various styles,
torus, sphere, cylinder and others. Given that with an Island 3 type habitat
you you begin to have problems with the wasted space of all that air above
you, there is a practical limit where it is not profitable to build them too
big.

So, my question is;
What kind of arrangement would the habitats be arranged into?

I know that there will be a number of solutions but for the most part would
they be singles (with an Island 3, by a single I mean the two cylinders
joined together), small clusters, either joined or just in close proximity,
giant clusters with thousands of habs, a mixed cluster a collection of
small joined clusters grouped together in large groups or some other system
that I havent thought of.

Some of my own thoughts, Australia is a very large country but with a small
population (just 20 million or about the population of New York state) and
while we have lots of valuable resources our workforce is small and the
income producing power is also small, a bigger population would help
generate a greater wealth base. When I hear about some group pushing to
break away from a nation I want to shake them and ask if they have thought
about the income problems they are wanting for themselves, before people
start emailing me about the other reasons why people want independence,
dont, I do know, I am just making a point. So like the EU and the euro (and
I know about some of the problems they have been having) grouping together
can have advantages and being near together can also have advantages.

That being the case I think that apart from the odd singleton (for
political/religious/ideological or even racial purity reasons)
they are going to be in clusters and mega-clusters. Consider a cluster of a
few dozen island 3s (population of 5 to 10 million each) in a frame that
keeps them aligned and in place, it could be used to run trains through,
transfer power and goods. Two island 3s (when I refer to an island 3 I mean
a 2 cylinder unit) with a pop of 10 million each would be the equal to
Australia, bring that up to 30 habs and you now have a population of 300
million, that is now a bigger population than that of the USA, with access
to energy and resources, this is a seriously wealth cluster.

If we call that a nation and then group a dozen such clusters together,
population 3.6 billion, to make a ... What to call it ... A union? A
commonwealth?, well, Australia is part of the Commonwealth so I think Ill
use that, this commonwealth would be the equal to 12 Americas, one hell of
a trade block. There a lot of advantages to groups of habs being close
together besides economic, one of the common strikes against habitats is
that once you are there you have no place to go, it gets boring, having a
cluster and a mega-cluster would give you the ability to travel.

What other ideas are their out there?

Darren Brown