First off, you cannotcan benefit from only one shield, as has been stated by @KRyan.
Armor/Shield Bonus: Each type of armor grants an armor bonus to AC, while shields grant a shield bonus to AC. The armor bonus from a suit of armor doesn't stack with other effects or items that grant an armor bonus. Similarly, the shield bonus from a shield doesn't stack with other effects that grant a shield bonus.
Most gaming circles I've been involved with certainly wouldn't mind a completely cosmetic aspect for some of what you have listed. Your character's primary hand being covered with an armoured gauntlet having no game effect still gives the same look, and it would be free. Some groups may not allow this, but it can't hurt to check.
Once you can afford having the buckler be masterwork, you can ignore the armor check penalty, and only take the -1 to hit when swapping from using the shield's AC bonus and attacking with the off-hand weapon. Adding Animated to the shield will allow you to make use of both the shield and the offhand attack for 4 rounds at a time during emergencies, but it is expensive.
The first few levels will be a bit rough, since the lighter weapons will end up doing less damage to start, and the penalties for two weapon fighting will mean you hit less frequently. This does eventually level out, though. Especially if you use weapons with higher crit ranges (18-20) like scimitars and rapiers for a larger weapon, and kukri for light off-hand weapons. Making these Keen or taking the Improved Critical feat will increase this to a (15-20) threat which is nearly a third of the time. Adding Critical Focus can make confirming the crits more likely. Ability draining poisons will help even more. Str drain will defend against retaliation, Int/Wis/Cha drain will help with casters. If you have enough feats, you can work up to Shatter Defenses, which can drop some enemies to Flat-Footed, but it requires adding other status effects which are hard to rely on without cooperation from a caster in the party willing to help.
Everything else depends on what class you take.
Warriors will benefit from dual wielding kukri, with Weapon Specialisation adding to your hit/damage rolls for both hands with just one feat. Same goes with only needing to take one of the Greater Weapon Focus skills to apply to both weapons.
As a rogue, it may be good to swap Str and Dex, if possible and make use of Weapon Finesse to hit more and make better use of Dex for AC. This can be added with Rogue Talents starting at level 2. Dispelling Attack can be added later to de-buff enemies. Combat Reflexes may also be good here, giving even more attacks as things wander by. The rogue build will be much more of a swashbuckling/fencer style, relying more on speed than strength. Sneak Attack dice will make up the difference in damage, when possible.
Rangers start getting dual wielding with their Combat Style Feats at level 2. Or you can start with dual wielding and get Double Slice for free at level 2. Favoured Enemy will also help with the attack/damage rolls, even against things that you cannot crit on.