DraQ
Arcane
No inventory space as such. Only equippable items targetting a number of slots. Some of those items may function as containers no mater if they also provide other functions (backpack, pockets in worn clothes, dagger with hollowed out hilt, etc.), providing tetris-y inventory grid smaller than their size (where you can put other items - including containers).Realistic inventories would be nice though.
JA2 1.13 and its pouch management (tm) comes to mind. Hard weight limits. Separate big sack inventory. Mules. Actual ones.
"Hard points" for certain big items.
Game builds and displays convenient tree menu for navigating those containers.
So, for example, if you are naked your inventory is limited to what you can hold in your hands (and then it occupies them), but you have slots on your body for worn stuff. If you put stuff on your body (like clothes, wearable containers, etc.) you start having actual inventory space to work with.
A cool thing about such system would be easy discarding, picking up and transfer of inventory, for example you could drop your backpack to not be encumbered in combat (or while fleing), take it off and stash it somewhere before swimming through the moat, maybe entrusting it to another character to get it to the infiltrated place via other channels.