I've posted an article with an example load test plug-in that allows you to specify the maximum number of test iterations for a load test: http://blogs.msdn.com/billbar/articles/533216.aspx

If you're interested in accessing the data in the load test results store directly to build your own custom reports or perform your own processing of the data, I've posted an article that describes the contents of each of the tables in the load test results...

Load testers sometimes need to clean up old load test results from the VSTS load test results store. The following SQL script deletes all load test results older than two weeks (though the timeframe is easily changed). If you have a lot of results...

I've posted an article on Implementing sync points in VSTS load tests at: http://blogs.msdn.com/billbar/articles/528649.aspx .