I've created a new version of the WCF Test Harness including some bug fixes and the ability to create a mock host.  This is a stubbed service based on a  loaded service contract.  This is very limited and its main purpose is to illustrate what is possible.  If this proves to be useful, I'll flush it out and work on its limitations and spend some time on the GUI.

Note: This replaces the previous version and is not compatible with the previous version (including the SampleHost.exe).

With this new release it is possible to perform the following:

1. First create a new client configuration and proxy by following: Add a New Proxy via Url.
2. Add a new test case and verify the service is valid by following: Creating a New Test Case.
3. Create a stubbed service based on the service contract downloaded in Step 1: Creating a Stub Service.
4. After stopping the TestHost service running, run the test created in Step 2 again.

This does have potential for being really useful.  The next step is to apply the test harness against some real-world services to see where the holes are...

As always, any feedback or suggestions appreciated.