I published my RowTest extension for NUnit in 2007. I developed it to experiment with the NUnit extension mechanism which was new in NUnit 2.4. It got some users and the extension was included in NUnit 2.4.8. NUnit 2.5 had the new Test Case feature which was built on the experience gained by the RowTest extension.
To switch from RowTest to TestCase you just have to replace the RowTest attribute by the TestCase attribute.
Since the RowTest extension isn't needed anymore I stopped its development long time ago. I just didn't publish an official statement about its end. I will remove the RowTest project page on my blog, but the project pages on Google Code and Launchpad will still be available: