Similar to how healer's kits are packed with medicinal herbs, perhaps create a pouch which can be filled with a particular object (only one type of object can go into a pouch, until it is emptied). When a summoning focus is used on it, one can then summon as if it were a summoning tome, but it drains charges.
Alternatively, for folks with GSF Conjuration, unlock a player tool that allows quick selection of reagents and tomes.
Thoughts?
Or, make it so that when a reagent is selected, when the summoning spell is cast, it uses up a different reagent of the same type than the one selected, unless there's only one. Similar to how medicinal herbs are, which lets you quickslot them.