You mean the boundaries on the very edge of the map?Is there any mods that remove the invisible boundaries on the map? That could increase the modding potential a lot.
IIRC it's not so much in need of modding but using the noclip command in the console.
Don't know if you heard but apparently someone did that days ago and found that both Morrowind and Cyrodiil are there but obviously empty and at a much much lower resolution.