Er. Is it just some wacky version of Wrye Bash I'm using, or even perhaps my imagination, or is it no longer as fussy about the top directory as some have been stating in this thread?
Seems that way to me, anyway. :shrug:
Package Structure
Bain recognizes three package structures:
? Simple
? If the package has esps, esms or bsa's at the top level, or if it has any of the regular Oblivion\Data subdirectories (specifically currently recognized are screenshots, bash patches, distantlod, docs, facegen, fonts, menus, meshes, music, shaders, sound, textures, trees, video, streamline, _tejon, ini tweaks, scripts, pluggy, ini, obse (last one only if option to install OBSE plugins is active)) at that level, then it will be categorized as a simple package.
? Complex
? If a package is not simple, but has subdirectories which appear simple (have esps/esms/bsas and/or have standard sub-directories), then it will be categorized as complex.
? In this case, each top level subdirectory (that appears simple), will be treated as a sub-package, and you'll be able to activate or deactivate it as desired before installing.
? Complex/Simple
? If a package is complex, but has only one sub-package, then it will appear as a simple package in the interface. (I.e. there will be no sub-package options.)
My highlight - That one sub-package can be called anything you want, even Data

I just consider sub-packages as separate selectable Data\ folders (with a unique name), each having whatever standard content you want, and each selected will overwrite the previous if it contains the same files.