Great news: it works!
(and I must admit that it was quite easy and that it took me far less time than expected)
So now you may switch to Python 3 with Spyder at your side.
For example, Windows users may already start working with a full featured scientific Python ecosystem including Spyder thanks to WinPython v3.3 which first beta was released recently. WinPython is now supporting both 32bit and 64bit versions of both Python 2 and Python 3, and all this in a portable way. In other words, with WinPython, you may run four versions of Python on the same machine without any prior configuration and without any interference: fast switching from a Windows-integrated (Windows explorer/registry integration) Python version to another is even possible!
Note that even if Spyder v2.1.14 supports Python 3, the forthcoming Spyder v2.2 release won't support it: Python 3 support will be officially implemented in Spyder v2.3 which will hopefully be released shortly after v2.2.