Hi Carl,
you can take advantage of Test Studio's extendability and override the OnBeforeTestList started feature to implement whatever logic you want in there:
http://www.telerik.com/automated-testing-tools/support/documentation/user-guide/code-samples/general/execution-extensions.aspx

The TestList class should give you access to the information you're looking for (test included in this list etc).

The datasources for your test project are stored under ProjectFolder/Data (e.g. C:\Users\stoichev\Documents\Test Studio Projects\TestProject75\Data) so you can easily write code to edit them. 
Getting the path to the project folder in code is easy:
http://www.telerik.com/automated-testing-tools/support/documentation/user-guide/code-samples/general/get-project-folder.aspx

Additionally don't forget about the Dynamic TestLists feature:
http://www.telerik.com/automated-testing-tools/support/documentation/user-guide/test-execution/standalone-test-lists.aspx#Dynamic

All of this information should give you an idea of how you can accomplish what you're looking to accomplish. Let me know if you need assistance with the heavy lifting (i.e. writing the actual code, figuring out how to make the plugin work and all of that stuff).

Accidentally, I'm doing a (free) "workshop" session on creating your own custom Test  Studio plugins this Wednesday so if you've got the time you should definitely sign up for that:
https://www1.gotomeeting.com/register/369331128

Greetings,
Stoich
the Telerik team