Experience Books

Players should be able to craft an Experience Book to store their experience orbs in case of death. To keep death meaningful, this book should have limited functionality and be difficult to obtain.

Use: Store up to 100 experience orbs, equivalent to 7.5 levels from level 0.

Recipe: 1 book, 1 ink sack, 1 feather, 1 exotic ingredient (redstone dust, glowstone dust, or lapis lazuli), and, most importantly, 1 bottle o' enchanting. 

Alternatively

Experience books could be implemented as loot in dangerous structures (Underwater monuments, End cities/ships, Nether fortresses/bastions, or strongholds).

These books should not be farmable. If the crafting recipe is implemented, the cleric's bottle o' enchanting trade should be replaced with a blaze powder trade or something of equivalent value.