Is there such a thing as unit test generation? If so...
...does it work well?
...What are the auto generation solutions that are available for .NET?
...are there examples of using a technology like this?
...is this only good for certain types of applications, or could it be used to replace all manually written unit testing?
I believe there's no point in Unit test generation, as far as TDD goes.
You only make unit tests so that you're sure that you (as a developer) are on track w/ regards to design and specs. Once you start generating tests automatically, it loses that purpose. Sure it would probably mean 100% code coverage, but that coverage would be senseless and empty.
Automated unit tests also mean that your strategy is test-after, which is opposite of TDD's test-before tenet. Again, TDD is not about tests.
That being said I believe MSTest does have an automatic unit-test generation tool -- I was able to use one with VS2005.