Gallio is a neutral test automation platform designed to help run tests from a variety of testing frameworks in a unified environment. It is a project that seems to be a spin off from the MbUnit team but will run tests from a variety of other frameworks including NUnit.
The Gallio Icarus test runner is somewhat similar to the test runner you get with Resharper. There is also a command line tool called Echo that has support for generating test reports etc.
Gallio also integrates with CruiseControl.Net. You need to setup your build to export a report in Gallio XML format (e.g. run Gallio.Echo.exe as a build task) and update the <publishers> node in ccnet.config. There is then a new report plug-in to be added to the CCNet dashboard to display the Gallio reports.