Thanks!
Mage Armor spell + Shield spell + buckler + "bracelets of armor +1" + "amulet of natural armor +3" while wearing a "+2 padded armor" will give you a grand total of:
+4 (mage armor spell) +4 (shield spell) = +8
I think you forgot about the bolded part.
It should be:
+4 (mage armor) +4 (shield) +3 (amulet of natural armor) = +11
Expanding the question...
Mage Armor spell + Shield spell + buckler + "bracelets of armor +1" + "amulet of natural armor +3" while wearing a "+2 padded armor" will give you a grand total of:
+4 (mage armor spell) +4 (shield spell) = +8
Shield spell won't stack with a shield.
Mage armor spell won't stack with an actual armor (neither the enhancement bonus to AC, which actually increases the armor bonus of the item and doesn't give an enhancement bonus to creatures -it's tricky because the enhancement bonus rules were part of the 3.5 DM Guide and the pathfinder explanation is terrible).
Mage armor spell won't stack with bracelets of armor.Note, however, that mage armor and shield spells are force effects. Sometimes it matters if the AC comes from force effects or actual items.
I.e. incorporeal attacks ignore shields and armor, but won't ignore mage armor neither the shield spell.
And any effect that makes mage armor and the shield spell useless won't render the other stuff useless.
To add to that: Though monks are not allowed to wear armor, bracers of armor (as the mage armor spell) are not armor, but still give armor bonus. So with this you can significantly boost your AC for classes like that. Like a sorcerer or wizard who would suffer arcane spell failure with armor but do not have that problem with bracers.
And sometimes, as mentioned above, it is helpful to have both real armor and mage armor /bracers of armor since if one does not apply or is dispelled, the other still might :-)