First of all: I REALLY like the Bonded Objects idea!
To say the truth, I like it MUCH more then the "old" familiar rules.
One thing to think about:
I would suggest giving the Wizard something like an Humunculus/Imp like Familiar instead of those Magically altered animals.
Something like using his blood to actually create the creature.
The Familiar rule might fit to "nature"-mages like Woodelves or the like, but not so good to those "Sarumanenous" wizards.
Hope you understand what I mean.