Hiya!
I'm going to be the odd man out yet again, and suggest:
talk to your DM.
Seriously. Explain what you want to do with your character concept, and see what you two can work out. Is he allowing Feats? All of them? Are there any changes? What about Multiclassing? Anything goes? Choose as you level, or do you have to spend a year in-game seeking a master, getting accepted, and training? And, most importantly, what style of DM do you have?
I once played in a game where I had a cool character concept (this is 1e days). The rules didn't work out to really enforce this concept (I think she was a "army/soldier battle mage" type). I talked it over with the DM. We came up with some cool ideas that fit (iirc, she could use a lot more weapons, and had spells she could 'attack/control' with that weren't normaly used that way...like using Dancing Lights to grant multiple weapons their own glowing property...that kind of thing). Anyway, another player had made a Magic User as well, and was kind of "upset" that my character "broke the rules";
his character couldn't use two handed swords, and
his character couldn't use Dancing Lights that way! Much whining ensued...even after we explained the whats, why's and wherefores of the situation.
So, if your DM is "open to suggestions" and fully embraces the "if it's not there, MAKE IT UP!"...I'm
sure you two can come up with something infinitely more cool than whatever you can finagle out of the RAW. However, if you have a DM who is...shall we say "lacking" in self-confidence or just is one of those "if it's not in the book, then NO!" types...well, ignore me and go with what others on this thread have suggested; they have more experience with "optimization as per the rules" than I do. I'm most definitely of the "creating something new is always better than trying to force the rules" type of DM.
That said...your character concept should come first, the rules on how to get there second. Playing your character as a in-your-face, protect others at all costs type of self-sacrificing character will serve you MUCH better than having an extra +2 on your AC. People in the game world will (should!) respect that and your character will become known for it. Maybe you'll have a town militia mayor come to your character to 'train us how to defend better'. Then maybe your PC will lead by example during an orc raid, with his newly trained "Shield-Men" turning the tide. Word gets out. Next thing you know you have lesser warriors coming to you for training in your technique and/or philosophy. ( and no, you don't have to have mechanical bonuses to back up
any of this...actions and attitude will speak FAR more than anything else). Before you know it...POOF! Your character is a legend and birthed an entire 'fighting style' that is used throughout the land! ... ... or you could just go with that Feat/Ability that gives you +2 AC like everyone else. Just sayin'...
^_^
Paul L. Ming