Masterwork and Magic Arms & Armor That Don't Make Me Cry Myself to Sleep at Night

[Ziegander]

As for 'small investment,' you have the same tools to make it work cheaply, since all you need for defending is a +1 masterwork weapon, so its 2k a weapon. Enhance Weapon gets you the bonus you need, so 4k for +10 AC is a bargain.

Except Enhance Weapon only lasts 1 minute, so the cost of maintaining a +10 AC boost will add up surprisingly fast. Add, you still have to sacrifice offense for defense if that's what you want to do, because you'll be dual-wielding two +2 equivalent weapons for a dubiously cheap +10 to AC when you could be dual wielding +20 equivalent weapons or so.