No, there is no designer. It would likely be difficult for a designer to even know what is meant by Razor code in many cases.
It’s really not so difficult to just use your web browser as a viewer. You can make changes to the HTML without having to recompile, just make the change, save, and refresh your browser.
EDIT (8/2/2013)
Since this answer was originally written, Microsoft has released Visual Studio 2012 which includes a feature called Page Inspector, which while not a true “designer” in the way that the question was written, it does give a much nicer semi-live preview mode. This has been improved in Visual Studio 2013 (which was RTM’d today, 10/17/13).