I was trying to write this game, and doing up my own rules with stuff from Talislanta, Dark Dungeons, D&D, Warhammer Fantasy RPG, and other influences, including material from excellent OSR blogs. This, though, is something of my own design, something that explains wizards' "toys," whether they be staves, wands, orbs, the fingerbone of a dead necromancer, a jaunty magical hat, or whatever: The Magical Focus Object, or MFO (That's one bad MFO, yo!).
Staves, Orbs, Wands, and Other Magical Focus Objects
At any point after 1st level, a magic user may create a Magical Focus Object (MFO). It does not matter what object is used, but the process is relatively expensive, and final step (casting) will consume (and destroy) the adjunct materials used whether or not it succeeds.
To create a focus object, a magic user will require an object with which to endow the power of focus object (e.g., a staff, wand, etc.), and materials costing 100 sp x Caster Experience Level squared. Thus, a sixth level magic user would need to spend 100sp x 6 squared = 360 gp for their MFO, a very expensive undertaking. [This assumed a silver standard, rather than gold, as discussed on Delta's D&D Blog: http://deltasdnd.blogspot.com/]
It is also very useful. The MFO doubles the effective mana pool for the spell caster, who may "charge" the MFO with raw mana, with prepared (e.g., "memorized") spells, or some combination of the two. Raw mana may be used to as part of the caster's mana pool for casting purposes. Prepared spells can be cast instantaneously, with only a single word or gesture, ignoring casting times.
The biggest drawback to the MFO is that it does not rise in level with its owner. Thus, a 2nd level MFO will only ever be 2nd level. This is offset by the fact that the caster may own (and carry) more than one MFO. However, each additional MFO creates the possibility for spell backlash, due to resonance with other MFOs. If the caster rolls a "Mishap" result on a casting roll, there is a possibility that any additional MFOs carried will explode, discharging its magical energy all at once. The spellcaster will take damage as if attacked with a Magic Missile spell of level equivalent to the exploding MFO.
If a casting mishap occurs where additional MFOs are carried, roll 1d6 for every additional MFO carried.
On a roll of "1" that MFO explodes; on a roll of "2" that MFO is destroyed without harming the caster; on any roll above 2, nothing else happens.
Caster takes level of exploding MFO times 1d6 in damage, with no possibility of saving throw. For example, a 4th level MFO would cause 4d6 damage.
Now, that's one bad MFO!
*Only a Magic User may create this.
Divine Relics [incomplete section, with just the ideas sketched out]
A cleric character is able to use a special kind of MFO: The Divine Relic. Unlike the magic user's MFO, the Divine Relic is a quest item. At 4th level, the cleric character may begin the process of acquiring a divine relic. The cleric must complete a process of research to locate it, and then go recover it. This is the basis for a hell of an adventure.
The Divine Relic functions just like a magic user's MFO for purposes of spell casting. However, it may have other benefits. Generally, this begin as minor benefits, but accumulate as the user gains in renown, through brave deeds, vanquishing foes, hewing true to their deity's laws, etc.
Rises in level with cleric.
Increases ability to rebuke or control undead as if the cleric is a level higher than they are.
Negates armor penalty for spellcasters.
Reduces magical and mundane damage by Experience Level of cleric.