Working on the Credit Returns system for Pfizer, I have started using the PLINQO CodeSmtih templates for generation of LINQ supporting classes. They have a few issues, but they generate separate files for all entities and give you some of the most common queries out of the box (e.g. get GetByForeignKey()) so you don't have to do the monkey work. They also give you absolute control over the output of your dbml files (e.g. it creates separate partial classes for each LINQ entity).