Last year I set up many TFS build dentitions for different environments (DEV, TEST and STAGE). When setting up different build dentition, I found TFS 2010 doesn't natively provide the feature of Clone Build Definition and it was really time consuming to set them up individually.
On Nov 26, 2012, I wrote a post entitled Fix the issue of Internal Error in Changeset in TFS 2010 . After installing TFS powerful tools 2011, the feature of Clone Build Definition appears in TFS 2010.
It is good news for me because I can clone many build definitions I want.