Just lately there seems to be a veritable feast of new blog stuff about VSX (if you don't mind me switching metaphors).  Some of these I stumbled across and some were pointed up to me by DuncanP.

• Oleg Sych now has a great series of T4 posts
• An explanatory series
• A series of patterns of T4 template design
• An article about creating a VS template for T4 templates
• A bunch of ready to go presentations on T4
• On the subject of T4 templates, Hilton Giesenow also has a post on a couple of T4 VS templates he's whipped up.
• Krzysztof Cwalina has announced the Managed Extensibility Framework - this is something to keep an eye on as it will play a role in Visual Studio eXtensibility in future.
• He also has a very neat post on the Simulated Covariance pattern for .Net Generics which is nothing to do with VSX, but funky nonetheless.
• Gokhan Altinoren has a neat demo of fronting a DSL Tool with a WPF-based design surface.
• David DeWinter has
• an article on using T4 to generate a complete set of sProcs for the new ADO.Net Entity Framework. It appears that he co-conspired on it with Ryan Hauert.
• A series on Dynamic Menu Commands in VSX packages

Phew!