Any .NET load-test tool available apart from VS2010 Ultimate?

Are there some tools which basically do the same as the VS2010 Ultimate load testing tool?

Anyone knows if there is a port of j开发者_StackOverflow中文版load or any other open-source load testing tools?

How about:

• The Grinder (http://grinder.sourceforge.net/)
• tsung (http://tsung.erlang-projects.org/)
• BadBoy (http://www.badboy.com.au/)
• Oracle Application Test Suite (http://www.oracle.com/technetwork/oem/app-test/index.html)

I fooled around with each one as a possible load testing alternative. They all feature distributed testing (except BadBoy, I think) and have interesting features, but none were compelling enough to overcome the large investment (anchor?) I already have in VS.