I recently came upon a 2011 document (pdf) from a local architect working in a suburb of Houston that I have become somewhat obsessed with. Basically, it's a pictorial account of how Houston—which has practically no land-use regulations at all—has developed as a city.
First, it sprawled outwards, but as the sprawl and population growth created more economic activity, and agglomeration benefits, the demand for housing near the centre rose and rose. Since there was no restriction on simply adding a few floors to buildings, and filling in gaps between them, to maximise the value of plots, and how many people they could accommodate, developers simply did this. And they did it beautifully and harmoniously, rippling outwards to make Houston denser and better.
The document, by architect Barbara Tennant, mainly tells its picture through stories, so you should check out the whole thing, as they say. But it has a few key lessons, repeated throughout: restrictions were minimal, with no height limits, freedom of style and design, and only a few rules on setbacks (how far properties must be from the street).
The results are impressive. Houston is cheap, diverse, rich, and growing, and this policy experiment should make us more sanguine about the results to London's skyline if we drastically reduced land-use regulations. The results of private development seem to be very attractive; by contrast planning restrictions seem to make things uglier and less popular.