I just wanted to share some news about TypeScript which is basically a super-set of Javascript that allows static types and traditional classes (among other features):
http://blogs.msdn.com/b/somasegar/archive/2012/10/01/typescript-javascript-development-at-application-scale.aspx
The compiler compiles to regular javascript. If you like using Intellisense (some don't) then TypeScript could be a great way to write the guts of your plugin in Visual Studio.