[Edit: The problem of eager-loading the stuff I ask for in expand is solved] I didn't remember when first writing the code and this post that I've got a DataLoadOptions override in a custom context wrapped around the original Linq to SQL model...
[Edit: This post is a continuation of this post . The latter contains some links to some of the code used. For instance VarianceWorkaround] It didn't actually turn out quite as I had hoped, (the DataServiceQuery don't know how to translate interface...