how about ...
Binder 1 / Urban Druid 3 / Anima Mage 10 / Tenebrous Apostate 5 / 1 x? (maybe a martial adept dip)
17th level binding, 17th level divine casting.
Anima Mage is reflavored to progress Divine instead of Arcane spell casting, class features untouched (no need to really).
Possible Feats:
Improved Binding (Important)
Ignore Special Requirements (Kinda Important)
Extend Spell (important as prereq for Persistent Spell)
Persistent Spell (Very important)
Power Attack (optional)
Leap Attack (optional)
Wild Cohort for tiger mount (Optional) (or reflavor the Vestige Andras, the Grey Knight's Mount ability to summon a dire tiger mount or something instead of a heavy warhorse. Probably better than wasting a feat on Wild Cohort)
Possible Spells to Persist (can persist 3 per day of levels 1-9):
Bite of the Werebear (A must, to have a somewhat decent BAB)
Brilliant Aura (optional, solves some BAB issues)
Venomfire + Poison Thorns (get attacked and attacker takes 17d6+ damage? *shrugs*)
tons of flexibility here (aside from the bite of the werebear spell, its a must with the anima mage's terrible BAB)
The idea behind this build can easily fit the concept of the character with very little reflavoring, and the character will be -extremely- flexible. Not only do you have the flexibility of the vestiges at your disposal, but also the flexibility of the druid spell list (which is already very powerful by itself). It'll be required to bind Tenebrous as one of the vestiges (thanks to Tenebrous Apostate), but this will allow the character to wade through hordes of enemies without a care. She'll also want to bind Andras if you decide to go that route for her tiger mount. If LA - Buyoff is allowed, the Feral template would help the character immensely in a variety of ways, (hell its even worth it without the LA buyoff). The build isnt too hard to optimize though, it has a few holes, but nothing that cant be managed.
Variety of spells to improve her tiger mount, such as nature's avatar, and im pretty sure theres one out there somewhere to increase its size. The character will probably want slippers of battledancing for the bonus Cha Mod to attack and damage. The character can wear medium armor, though is limited to light 'metal' armor due to urban druid. But this can be bypassed by creating ironwood medium armor, or ironwood heavy armor if the 1 level is invested into a class that is proficient with it, rather than the feral template.
I believe this meets all the requirements yes? ^_^
Edit: Woops, this might be a bit over the top if the DM is paranoid xD.