Just make a new Personal Bank Contact NPC in Social District for players. Put him in the Galleria. Call him Vault, he has no faction. He can hold Weapons so you don't have to scroll through a massive list when resupplying or changing guns, Consumables, Themes, Clothes etc. Overfill items go to the Vault by default of your mail. Make him have a good amount of inventory space and you can earn more slots from new upcoming contacts or Joker Tickets maybe?