Below is a suggestion I made on a different topic and I think it could work for this as well. A key ring of some sort has been suggested many times because it has obvious benefits.
The "quick access pouch" as I called it then could hold both PvP items (stubs and potions), these new upgrades that are being discussed, or some combination of those items.
viewtopic.php?f=8&t=17910&hilit=Key#p127806
Maybe create two extra additional storage locations:
One is a key ring. You get 1 regular storage page (20 spaces) for keys and only keys. Solves that issue many players have. (Not everything in the game revolves around clans and PvP. )
Second is a quick access pouch. You get 2-3 regular storage pages (40 or 60 spaces) and can carry health pots, mana pots, speed potions, freeze potions, or stun items. You can carry whatever combination of those items you want.
Backpack can be used just like it is now. If you have the same items in your backpack and your quick access pouch they come from the pouch before the backpack.
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