What about spellstaves with runic patterns upon them representing various spells? Because such staves have only so much room upon them, perhaps state they are limited to 100 runic patterns - and each spell requires as many runic patterns as its level +1. Spell staves are basically quarterstaffs in many respects. Small staves - wands - are basically short clubs and can only hold perhaps 25 - 30 runic patterns. Each runic pattern adds +1 to the spellstave's hit points, and the highest spell engraved upon it determines its bonus hardness. So a spellstave with one spell of each level would have +45 hp and +9 hardness over a typical quarterstaff. This would probably not effect its damage output if it were used in such a manner, of course.
Most NPCs are no higher than tenth level, and the vast majority are no higher than fifth level (by which time shrink item is known). Most wizards would wander about with a single spellstave always enlarged, seemingly a walking staff from a distance, but closer an obvious statement as to the wielder's class (a sort of badge of rank, in a way). "Higher" level ones (5+) will likely also have a "spell-component" pouch that in fact has shrunk extra spellstaves and wands. A wand or two may even hang from his side - and almost certainly will for "mid" level ones (2 - 4, not yet having access to Shrink Item).
Semantic components may be used through the staff - waving it, passing it mystically over an item, drawing patterns in the air, etc. All casters effectively have Eschew Material Components - only costs more than 1gp need be considered. This is balanced by all casters requiring the wielding of their staff to wield their magic. The difference between the wizard and the sorcerer, therefore, is that the wizard determines the necessary runes through study while the sorcerer determines each intuitively. The wizard notices similarities between certain runes and derives one with the properties desired. The sorcerer sees an interesting pattern one day (perhaps the patterns of light reflecting off various clouds in the morning sky) and intuitively realizes that this pattern - if carefully engraved and later invoked may grant him the ability to perform a specific magical act (in the prior example, perhaps Daylight or Hypnotic Pattern or Color Spray, etc).
Anyway, that is how I would consider doing it.
I've actually been thinking about something like this for a while, but I've also been creating a new magic system (based loosely off the EoMR, but with spell skills, elemental feats, complex skill checks, etc).
