Forestry backpacks can be upgraded to 45 slots (from 15), but the recipe is such that by the time you can craft it, you don't need the backpack anyway.
Changing the recipe to be simpler (not requiring hours of work into bees) could make people actually use these upgrades.
(alternatively, you could make upgraded backpacks available for purchase at spawn)
P.S. The adventuring backpack is supposed to be configured. Maybe we could do something with it.
Forestry backpacks can be upgraded to 45 slots (from 15), but the recipe is such that by the time you can craft it, you don't need the backpack anyway. Changing the recipe to be simpler (not requiring hours of work into bees) could make people actually use these upgrades. (alternatively, you could make upgraded backpacks available for purchase at spawn)
P.S. The adventuring backpack is supposed to be configured. Maybe we could do something with it.