I've got an idea for a mod that would make the inventory look nicer while also organizing things.

Step 1: custom font characters. Crack open the font the game uses and re-draw certain characters as icons. There are greek and cyrillic alphabets in there that aren't doing anything useful (at least, not in a US localized game). Change some of those characters into little monochrome pictures of swords, armor, and whatnot.

Step 2: change the names of every item to include those special characters. For example, change "Iron Sword" to "Ж Iron Sword". If you've redrawn the Ж character to look like a sword, the item now shows up in game with a nice little icon.

Here's the clever bit - because the game sorts items alphabetically, all similar items will be sorted together. So, when you look at your apparel, your helmets would all be grouped together. Your miscellaneous items would be nice and tidy would your soul gems all together in one place and your ingots in another. Perhaps unique icons could be set up for different potion effects, so those could be organized too.

I think it would be possible to put this together with the tools currently available, but it would mean a huge amount of incredibly tedious work. Also, once a mod like this is made, it tends to be very incompatible with other mods. Converting the mod to .esm and getting community support is the only good way around that.