GetModule returns a Module instead of a ModuleBuilder, so its not really what I'm looking for. Also, the docs for AssemblyBuilder says:
"Some methods on the base class Assembly such as GetModules and GetLoadedModules will not work correctly when called AssemblyBuilder objects. You can load the defined dynamic assembly and call the methods on the loaded assembly. For example, to ensure that resource modules are included in the returned module list, call GetModules on the loaded Assembly object."
I'm not quite sure what about GetModules thats not working, but I'm not using it :)
/Chris