Niner since 2009
Dynamic Dictionaries are really easy to create in .NET 4, I did a post on it here: http://www.aaron-powell.com/dynamic-dictionaries-with-csharp-4 and although you do loose the intellisense
capabilities I think that'd be a small price to pay to have a simplified data management method.
Having ViewData and ViewModel could get confusing (unless ViewModel is just a wrapper on ViewData) and it'd make testing harder as you need to ensure that the data is being added to the "right" collection.
What build of VS2010 was that demo using, the CTP. It didn't look like the beta 1 release