Colin Eberhardt has a nice article on The Code Project walking through using a small textual DSL encoded in XML to define a set of dependency properties and then using that as a data source for T4 to generate all of the necessary boilerplate code.

Apart from being intrinsically cool, he's also doing this in a Silverlight project, and he includes the small amount of special sauce needed to get T4 generation working in a Silverlight project inside Visual Studio 2008.

 

BTW, in Visual Studio 2010, T4 in Silverlight should "just work".