There are numerous companion mods with an option like that. IIRC correctly there is only one thing that can't be worked around - chairs and beds need to be persistent references or the AI won't use them.
Aye, there be. I use http://www.tesnexus.com/downloads/file.php?id=8256. Here you see her sleeping in a guest room at Verona House.
1.) http://i307.photobucket.com/albums/nn303/Decrepit_Waste/ESIV%20Oblivion/NeeshkaSleep_2.jpg. (A fluke. She is supposed to sleep in her undies, or less depending on your body-replacer of choice.
2.) http://i307.photobucket.com/albums/nn303/Decrepit_Waste/ESIV%20Oblivion/VeronaNeeshkaWake_1.jpg.
And here she is captured on break during two separate quests. If I sit down, so does she. And when she sits, she often eats and/or drinks.
3.) http://i307.photobucket.com/albums/nn303/Decrepit_Waste/ESIV%20Oblivion/ImpBridgeInn_1a.jpg.
4.) http://i307.photobucket.com/albums/nn303/Decrepit_Waste/ESIV%20Oblivion/NeeshkaBravilInn_1.jpg.
-Decrepit