Hi,
I regularly write EventArgs classes. These derive from EventArgs and I usually add 1 or more additional properties. To speed up this development I created a snippet that extends Visual Studio Refactoring capabilities.
Basically I just copied some other code snippet and I changed the code a bit. Its very intuitive!
you can download the file here
To install this, go to the Snippet Manager on the Tools menu and import this snippet file.
The snippet will produce the following code:

BTW, don't forget the large extension of code snippets from Microsoft.
- Erik