I have always struggled to find a nice easy way to create cartograms. That was until I found a relatively new tool called ScapeToad (http://chorogram.choros.ch/scapetoad/). Within minutes I had generated a very appealing cartogram of London at Output Area level. Convenient features include: the ability to export back into ArcGIS, the output of the distortion grid and the ability to manipulate multiple layers based on the same distortion. All a very promising start!