If you want to see per-test reporting during TeamCity build-running, with NUnit 2.5.3 (which isn’t mentioned as being supported in the TeamCity v2.5.3 release notes, but actually seems to be fine) executing tests via a command-line command (instead of TeamCity’s built-in NUnitLauncher), where your nunit-console.exe is stored in source-control, you need to:

  1. Jump onto an agent machine
  2. Open up {agent-install-dir}\plugins\dotnetPlugin.zip\bin
  3. Pull out JetBrains.TeamCity.NUnitAddin-NUnit-2.5.3.dll and .pdb
  4. Drop those into your {nunit-in-source-control}\bin\net-2.0\addins directory in source-control
  5. Commit
  6. Marvel at the per-test reporting that then happens (because a build will kick off)

Thanks to John Leger for getting me most of the way there :-)