We have not had a request for WebSockets plug-in so far, but our planning is driven by customer demand, so if you suggest this functionality on our Feedback Portal
and it gathers enough votes, we'll have it in mind.
In general you can read more about our plans for generic plug-ins support in the following forum thread.
the Telerik team
Share feedback and vote for features on our Feedback Portal.
Want some Kendo UI online training - head over to Pluralsight.