Here it is. I refined the earlier approaches to render a stereoscopic VR sphere including the toon shading and the freestyle lines in resolution of 4096×4096.
It has some artifacts in the freestyle lines and some sawtooth distortion especially in the upper and lower part. But as the equirectangular projection highly compresses those parts it looks good to me on my VR headset which is a Google Nexus 5 (Full HD resolution) using vrPlayer.
Just klick on the image to download the large version.
I hereby release this image to the public domain using the CC0 1.0 license : http://creativecommons.org/publicdomain/zero/1.0/
Have fun with it.
Chuck Ian Gordon
P.S.: You can find some more information how to use it here: http://www.blenderartists.org/forum/showthread.php?361867-PERFECT-VR-TESTCARD-done-with-blender-and-a-short-tip-how-to-do-it