People... you don't need Light Armor Proficiency with a Wizard. What happens if you are not proficient with the armor you're wearing? You suffer its ACP on all attack rolls and skill checks involving movement. Meaning, if you use an armor with 0 ACP, you suffer absolutely no penalty. Now, depending on your resources, you could use:
- Thistledown padded armor (RotW) 405 gp (+1 AC, no spell failure, go and add some enhancements)
- Wand of Mage Armor 750 gp
- Several minor AC boosters: bracers of armor, ring of protection, amulet of natural armor...
- +1 twilight mithral chain shirt 5100 gp (quite expensive, but hey...)
- Extend spell + Mage Armor, once you hit CL12 your armor lasts the whole day!