Scaling / Fixed / Unchained Two Weapon Fighting

[master_marshmallow]

You can fight with a weapon wielded in each of your hands. You can make one extra attack each round with the secondary weapon.

Prerequisite: Dex 15.

Benefit: Your penalties on attack rolls for fighting with two weapons are reduced. The penalty for your primary hand lessens by 2 and the one for your off hand lessens by 6. When your Base Attack Bonus reaches +6, in addition to the standard single extra attack you get with an off-hand weapon, you get a second attack with it, albeit at a –5 penalty. When your Base Attack Bonus Reaches +11, you get a third attack with your off-hand weapon, albeit at a –10 penalty. When your Base Attack Bonus Reaches +16, you get a fourth attack with your off-hand weapon, albeit at a –15 penalty.

Normal: If you wield a second weapon in your off hand, you can get one extra attack per round with that weapon. When fighting in this way you suffer a –6 penalty with your regular attack or attacks with your primary hand and a –10 penalty to the attack with your off hand. If your off-hand weapon is light, the penalties are reduced by 2 each. An unarmed strike is always considered light.

[LoneKnave]

Do you really want unchained?

Benefit: Whenever you make an attack while wielding two weapons, you may make instead an attack with each weapon at a -4 penalty to both attack rolls if both of them are one handed, or at a -2 penalty if at least one of them is light.

There. You can now use both weapons after moving, when charging, on AoOs, even with Vital strike, and you aren't chained into one spot if you want to do so (which is in stark contrast to the whole whirling dual blade dervish archetype thingy).

[Marc Radle]

You could always just pick up a copy of the New Paths Compendium which has an entire section on Scaling Combat Feats, including Scaling Two-Weapon Fighting (which the OP's version above looks to be a more or less exact copy of ...)

[rainzax]

Twin Stroke
Prerequisite: DX 15, Fighter or Monk 8th
Benefit: You may attack with two weapons on your turn any time you could normally attack with one - such as part of a standard action or during a special full round action that involves a single attack. You suffer no penalty to your attack roll if you direct your attacks against two different opponents, but your secondary attack suffers a -5 penalty if you direct it against the same foe as your primary attack.