I think that the success of windows tablets will rest on how well it can actually run windows programs. I think it will get the 10% share you listed just by name alone, and when people see it in their local best buy, they will like it cause they are familiar with windows PC's. 
However, I don't think it reaches much more than 10% unless the price is insane. iPad has become a trademark name for tablets, so they are going to continue to sell like crazy. Android has produced many levels of tablets, which allow users to really pick and choose price wise. I think it is most likely however, that Android will lose more market share to Windows than iPad will. 
I really want to play with Windows 8 on a tablet, cause if it can do what I want, I will be getting one.