Please describe the new feature or change.
The ability to change how long it takes for the items the player drops on death to despawn. Perhaps have an option to never despawn, and then one for any minutes:seconds value?

Please describe why you want this feature.
The main reason I use any sort of tombstone/grave/deathchest mod (and I'm sure the same is true for many other players) is because it can take a long time to find, and especially get to, where you actually died. By the time you find your way to the cave you died in, your items are long gone. I'd love to have a feature like this because it'd be so much simpler than getting frustrated over losing special items (baubles, for example) because the specific tomb/grave mod you decided to use doesn't support those extra inventory slots and doesn't save them to the grave.