Although lot's of people want this idea to come true, it will not happen as for example if you could deposit a weapon with 0 bullets, the plugin would have to keep track of that in some sort of database, it's just way too tedious.
This would be too op as players would be able to put their weapons away before they die with a simple script and it would ruin the fun.
If you're going to take something out of your inventory, use it all up before you die.