There are a whole bunch of mods that improve various textures. Are there any mods that change the meshes so that when you pick an item up in game it doesn't turn upside down? Really, trying to put something right side up on a table is ridiculously hard. The center of gravity is all wrong for most of the meshes.

Not sure about that but http://www.nexusmods.com/skyrim/mods/8655/? fixes A LOT of mesh errors in the game. It's a MUST HAVE for me.

http://www.nexusmods.com/skyrim/mods/33395/?? The nexus page doesn't adequately describe what the mod actually does.

http://www.reddit.com/r/skyrimmods/comments/1dbfry/mod_more_precise_object_manipulation/.

The Unofficial Patches fix a bucket load of mesh problems, including collision boundaries among many other mesh problems.

http://afkmods.iguanadons.net/index.php?/topic/2804-relzwipz-unofficial-skyrim-patch/

http://afkmods.iguanadons.net/index.php?/topic/2805-relzwipz-unofficial-dawnguard-patch/

http://afkmods.iguanadons.net/index.php?/topic/3573-relzwipz-unofficial-hearthfire-patch/

http://afkmods.iguanadons.net/index.php?/topic/3579-relzwipz-unofficial-dragonborn-patch/

If there is any particular item they do not fix ..

Report it http://afkmods.iguanadons.net/index.php?/tracdown/

Try to get a RefID for the objects and locations ( as much info to pinpoint the exact mesh as possible )

Then eventually it will get fixed ( if possible ), and we all benefit

I think what you're talking about is that, whenever you grab something in Skyrim you grab it by the very center of the object, instead of wherever your crosshair was looking at like in Oblivion. Is that correct? I don't know of any mod that changes this, and it's not a problem with the meshes themselves. Buuut if one exists I want it so bad oh my god.

Not sure about any mods that alter the interaction of models with the physics engine, but there is a positioning mod that allows you complete control.

http://www.nexusmods.com/skyrim/mods/52583/

Yes. That is one of the most exasperating things about Skyrim. I had hoped there was a fix that I hadn't heard of. Is it a problem with the engine itself or how the meshes were made?

I believe it's because the origin of a mesh is usually located at its base. The location and rotation of the origin is the object's true location and rotation.

If you're decorating your home - or just want to lock items in place so that they don't fly everywhere when an NPC sits down at a bloody table - then use http://www.nexusmods.com/skyrim/mods/52583/?