(The same goes for anyone out there with alternate magic systems...)
Not really an alternate magic system, and not really quite finished, but nevertheless:

http://www.geocities.com/m_aurel_pod/wizardstaff.doc

You might have to do a right click and save or something on it; I hope the link works.

Basically, that's my system for replacing familiars with special staffs for wizards. Familiars are a pretty powerful benefit, so a wizard's staff is similarly strong. I'm not quite sure whether all the benefits are fully internally balanced, and all of them might not be fully appropriate for a Birthright setting. There are also some parts of the system that I've revised a bit since writing that document - such as allowing wizards to change staff materials and qualities.

For those who don't want to download and read the document, a quick summary of the system:

A wizard's staff has a material type (wood, iron, bone, whatever) that defines the staff's durability, material cost, and a material ability - either a damage bonus against a specific creature type (including on spells cast) or another form of bonus, such as a skill bonus. I thought about having multiple types of wooden staffs, but haven't had time to research appropriate types and appropriate bonus types by tree yet.

A wizard's staff can hold a single spell - the wizard can spontaneously replace any spell he has prepared with this one in the same way that a cleric can cast cure spells. Pretty powerful benefit, but not really gamebreaking. So far, most players seem to put an offensive spell in the staff (not necessarily their highest-level such, either) and prepare an additional utility spell or three instead, which I like - it makes wizards somewhat less of a fireball turret.

A wizard with his staff can generate a protective circle against a school of magic as a full-round action; a specialist is a bit better against his own school, of course (four levels ahead). At 1st level, this grants a +1 save bonus; at 2nd, it grants immunity to 0-level spells, at 6th, it grants a +2 save bonus, at 10th, immunity to 1st-level spells, at 14th, SR, and at 18th, immunity to 2nd-level spells. Thus, a 1st-level wizard could, in 8 rounds, generate a circle that granted a +1 bonus against all spells. A 1st-level enchanter could generate a circle that granted a +1 bonus on saves against enchantment spells and immunity to enchantment cantrips (daze) in one round. Not really that powerful an ability by itself, but it can help, especially in some encounters, and it's not a use-limited ability, so a wizard can use it any time.

Finally, there's special abilities at every 4 levels, starting at 4th. These are abilities to individualize a staff a bit more, such as the ability to bolster undead with a protective circle, or the ability to ignore hardness when striking objects ("you shall not pass"), or a simple +1 caster level with spells from a specific school.

That's about how it looks. It may seem powerful, but bear in mind that wizards can gain a tremendous amount of versatility from their familiars as well, in terms of information gathering, using touch spells, and even as a secondary combatant.