No, there is not. I’ve figured out. But this is just the way it is.
The main reason I wanted to figure this out, is because I was using generated DataSets and tableAdapters and wanted them all on a sub namespace. To do this, all you have to do is set the “Custom Tool Name” property of the dataset and that will be the sub namespace.
Some people say that you could place your class files within “Folders” in the solution explorer, and each Folder becomes a sub namespace, but that didn’t work for me. If someone has the answer to this, please post it.