One highlighted and always developing regional cluster between Sweden and Denmark.
Around one year ago I attended a symposium on biotechnology hubs. Finn Valentine from CBS had a presentation based on biotechnology patents in the Medicon Valley.
This video seems to be a promotional video to the South Swedish region for investors. I only include here to get a feel of Medicon Valley.
Clusters are often approached by economists and political scientists from a policy perspective. Here is a social science perspective using networks.
Research from Jason Owen-Smith (eg.2004, 2005, 2009 papers) has always been very exciting. Here he talks about clusters and their inner mechanics in respect to demographics of talent and technology.
(Additional Info: TRE Networks Roundtable and Annual Meeting, Washington, D.C., Dec., 5-7, 2012)