where did NUnit Gui Runner go? version 3.0.1

The NUnit team decided to make the GUI a separate product and will be releasing it separately. It is being rewritten from the ground up for NUnit 3, but hasn't been released yet. Development is happening on the GitHub page at https://github.com/nunit/nunit-gui if you want to get involved or track the progress. Initial releases will be out soon.

Update - There have been several preview releases of the new NUnit GUI that can be found at https://github.com/nunit/nunit-gui/releases. The previews are not recommended for production use, but they work and can be used.

The "final" release is here, you can find it at: https://github.com/TestCentric/testcentric-gui/releases

For anyone coming to this page, looking where to find the NUnit Gui, please note that on http://nunit.org/?p=download you can get version 2.6.4, which does contain the Gui.

UPDATE

As pointed out in the comments, a lot has changed since, and you should no longer use the 2.x version tools, rather use the new TestCentric UI found at https://github.com/TestCentric/testcentric-gui/releases