What a week! Hot on the heels of MDDE appearing on Codeplex, another internal MS solution for generating SSIS packages dynamically appears. I saw a Vulcan demo a couple of months ago, and was really impressed. It generates SSIS packages from XML definition files, making it very to create template solutions.
I haven't had a chance to finish my MDDE write up, but once I do, getting Vulcan up and running will be my next project. I don't see any docs up for it yet, but I'm sure they'll be appearing soon.