Late submission, I know... I was hoping to get it up earlier as a bump, but got bogged down with classwork, which prevented me from getting it up in time to be a useful bump. With that, here's my submission...

All of the following feats gain a benefit from being outnumbered, which increases as you are outnumbered more drastically. The factor by which you are outnumbered (number of enemies divided by number of allies, counting yourself, rounded down) is denoted as X in the feats. As such, if you are outnumbered 2-to-1, X is 2, if you are outnumbered 3-to-2, X is 1, if you are outnumbered 3-to-1, X is 3, and so on. You must be aware of enemies for them to count, and they must be within 1000 feet, plus 100 feet per caster level. If a character is charmed, helpless, sleeping, unconscious, confused, feared, or otherwise not in control of their actions, they are counted as neither an ally nor an enemy. If dominated or otherwise turned against their former allies, they are counted as an enemy instead. If you are not outnumbered (equal or greater number of allies [including yourself] than enemies), you are unable to use any of these feats. Swarms count as a single enemy per swarm unit for the purposes of these feats (2 rat swarms is 2 enemies, but an advanced rat swarm that takes up additional spaces is still only a single enemy). If you kill one or more enemies with a spell on your turn and want to use one of these feats for another spell, recalculate X.

If more than one character has a feat in this series, an alternate method of determining X is recommended: at the beginning of each initiative round (before the character with the highest initiative count acts), calculate X for each character with one of these feats. Those characters then use that value of X for that round, but may only use any feats on the first spell cast in the round (exception: Resolute Caster may apply to the second if the first spell cast isn't a personal or touch range spell cast on yourself).

Resolute Caster [General]
You are able to protect yourself from the dangers of being flanked by enemies who have you outnumbered.
Prerequisites: Ability to spontaneously cast spells.
Benefits: Whenever you cast a spell with a range of personal or touch on yourself, you negate the benefits normally acquired by enemies in a flanking position for X rounds. This includes, but is not limited to, the +2 bonus on attack rolls and sneak attack damage. If your opponents have another way of acquiring benefits (such as sneak attack) that can also be gained through flanking, this only prevents them from gaining that benefit from flanking (in other words, you can still be the target of a sneak attack as normal, but the rogue must catch you flat-footed somehow rather than being able to gain the sneak attack from flanking).
Normal: Being flanked by enemies provides them with a +2 bonus to melee attack rolls against you, plus possible benefits from class features.

Metamagic of the Resolute [Metamagic]
Not only does being outnumbered cause you no fear, you can use the danger to improve your spellcasting ability.
Prerequisites: Ability to spontaneously cast spells, any 1 metamagic feat, Resolute Caster, Spellcraft 4 ranks.
Benefits: When you and your allies are in a fight in which you are outnumbered, you are able to harness the danger to improve your metamagic spellcasting. This allows you to apply X metamagic feats to a spell you cast without increasing the casting time of the spell. You can apply this to a number of spells each day equal to the highest level spells you are able to cast.
Normal: Applying metamagic feats to spontaneous spells causes the casting to require a full-round action.

Adrenaline of the Resolute [Metamagic]
You can harness the adrenaline from being outnumbered to power your metamagic feats, reducing the cost of applying them.
Prerequisites: Ability to spontaneously cast 3rd level spells, Resolute Caster, Metamagic of the Resolute, any 1 additional metamagic feat, Spellcraft 8 ranks.
Benefits: When outnumbered, you are able to reduce the cost of applying metamagic feats. A number of times per day equal to the highest level spells you can cast, you can reduce the total adjustment from metamagic feats to a single spell by X, to a minimum of +0 levels. This reduction occurs after any other cost reductions you may have to the costs of metamagic feats.
Special: This can be used in conjunction with Resolute Metamagic, allowing you to cast the spell, with metamagic feats applied, as a standard action with reduced cost, but doing so counts as one use of each feat.

Resolute Mastery [Metamagic]
You have mastered the art of channeling your adrenaline into your spells, allowing you to cast more spells than normal while you are outnumbered.
Prerequisites: Ability to spontaneously cast 5th level spells, Resolute Caster, Metamagic of the Resolute, Adrenaline of the Resolute, any 1 additional metamagic feat, Spellcraft 13 ranks.
Benefits: When outnumbered, you are able to cast spells without using spell slots. A number of times per day equal to the maximum spell level you can cast, you are able to cast a spell of up to level X without using a spell slot, to a maximum of your normal maximum spell level, after any adjustments for metamagic feats or other features. Adding metamagic feats to these spells does not increase the casting time of the spell, and does not count against your daily uses of Metamagic of the Resolute.
Special: The benefit provided by Resolute Mastery can be combined with the benefit from Adrenaline of the Resolute to reduce the cost of applying metamagic feats to the spells gained from Resolute Mastery as you would for any other spell. For example, if you are outnumbered 2-to-1 and have the appropriate feats, you can cast a Stilled Silent Shatter (a level two spell with two +1 level adjustment metamagic feats, the total cost of which is reduced by 2) using one use each of Resolute Mastery and Adrenaline of the Resolute. Without using Adrenaline of the Resolute, you could cast a Shatter or a Silent Magic Missile (or any level one spell with a +1 level adjustment metamagic feat) with that same free "slot" as a standard action.