I've just released version 2.4.0 of the VSTS Extension Project Template extension for Visual Studio. This release includes a new Item Template for the Dashboard Widget. Special thanks to Utkarsh Shigihalli for the suggestion! The template itself is quite basic but will get you moving in the right direction. For more information on dashboard widget development, please refer to the fabulous VS integration documentation. You can also refer to the ALM Rangers blog post on creating widgets.
As always, candid feedback is welcome!