Dunno if this has been posted but its morrowind in oblivion
"Mod for The Elder Scrolls IV: Oblivion that brings The Elder Scrolls III: Morrowind into Oblivion. This mod converts the Morrowind game files so they are compatible with the Oblivion engine. This means that we can explore the island of Vvardenfell with Oblivion graphics, physics, and interactivity levels.
Take a looks : http://morroblivion.com/