A while back I posted about the algorithm used for creating a test ID within VSTS Test Lists. I also made mention that I was writing a utility that allowed for basic test list management and unfortunately more time has passed between that post and me actually putting something out there for the community. In all honesty, this tool is very basic and I haven't had much time to work on it, but I hope it is feature complete enough to at least be usable by people wanting to create test lists for their build process.
When using this tool, the vsmdi file created must be at the solution root for the project (which is where VSTS puts it when they create it - this tool won't default to that location, but that is where it needs to be put). To create a test file, go to File->New and create the test list file (name it with a .vsmdi extension). When the file gets created, there are three nodes in the tree view (Lists of Tests, Tests Not in a List, All Loaded Tests). To add test lists to the file, right click on the Lists of Tests node and select "New Test List...". Within the new window, type the name of the test list and click OK. Test lists can be nested and you can create as many test lists as you like, but they must only be created under the "Lists of Tests" node. To load up tests, select File->Open and select .dll for the file filter. Navigate down to the location of your test assembly (test assemblies must be somewhere within the same directory tree as the vsmdi file) and load the dll into the application. Select the All Loaded Tests node to view all the tests within the test assembly. Expand the Lists of Tests node and drag tests from the grid to the correct test list (the Test List field in the grid will get populated with the fully qualified location of the test). Select File->Save to save off the vsmdi file and now this file should be usable by Team Build for your unit test execution during a build.
Here is the source for the management tool, hope you find it useful. If there are missing references, the location for the 2 files is C:\Program Files\Microsoft Visual Studio 8\Common7\IDE\PrivateAssemblies and you will need Microsoft.VisualStudio.QualityTools.Common.dll and Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel.dll.
Please let me know your experience with this utility (good, bad, or otherwise).