Thanks for the suggestion. We will consider a Notification UI widget for Kendo UI in the future.
As you may be aware, there is a specification in the HTML5 working drafts for a browser-implemented Notification API. This API gives HTML5 apps the ability to deliver true desktop toast notifications (displayed outside the browser shell). Unfortunately, support is very limited today (only available in Chrome), but hopefully that will change soon.
You can learn more about this native API here: http://www.html5rocks.com/en/tutorials/notifications/quick/