Item slots, so far as I can tell, represent the need to maintain the enchantments on items. Without magic, you can't do that.
Anyway, here's a custom Power for ya.
BAG OF TRICKS [-1]
Description: For whatever reason, you have access to a few minor magical trinkets.
Skills affected: Contacts, Resources, Burglary, Lore.
Effects:
Enchanted Items: You have four potions, each with a strength equal to your Contacts, Resources, Burglary, or Lore skill. You may not increase their strength in any way. At the beginning of each session, you must declare which potions you have on hand.
More Trinkets [-1]. You have four additional potions. Furthermore, you may choose to leave potion slots open to be filled later with Declarations.