http://m.bbc.com/news/technology-32658340
This is a bit of a sensationalized article, but it is interesting that MS may be stopping at version 10.
Although as I understand it, the article is wrong in one area: They skipped 9 not because 10 was such a substantial difference but because so much software used string matching to check the Windows version rather than checking the actual Windows version (which means that matching "Windows 9" matches both "Windows 9" and the "Windows 95/98" series). Oh, the irony.