I don't have much time to really look at this closely, but just wacking something up that makes using a rapier and leather armour optimal and has a slightly swashbuckler feel ... okay ... arcane swashbuckler?

Its a pity its too MAD to go Rogue as Multiclass (requires DEX 13) as Sneak attack would be nice for this build.
Quick note: Yep you lose leader healing powers but as far as defenders go your swordmage aegis can save a lot of hps
I'll post now and edit later when I have time:
level 6
Human, Warlord|Swordmage
Warlord Leadership: Combat Leader (Hybrid):
+2 to allies initiative; Hitting first is always advantageous
Hybrid Warlord: Hybrid Warlord Will
Swordmage Aegis (Hybrid): Aegis of Shielding:
You can mark an enemy 2 squares from you; If they don't attack you they get -2 to the attacks the make against other targets. 1/round you can interrupt an attack this marked enemy makes against your ally and reduge the damage by 7
Hybrid Talent: Swordmage Warding:
Via Hybrid Talent feat gain +3 AC bonus if you have a sword in one hand and nothing on the other; Your AC is very decent with this at level 1. As high as a fighter in Scale Armour with a heavy shield. Only a paladin in plate with a heavy shield can pip you by one point, but then again they have a massive armour penalty to all physical skill checks. You have zero such penalties.
Human Power Selection: Bonus At-Will Power
Background: Society - Noble (+2 to Diplomacy):
I have a feeling you prefer Intimidate, as it fits your character better, but Diplomacy is probably more useful. Simple to change in any case
FINAL ABILITY SCORES
Str 16, Con 14, Dex 10, Int 19, Wis 8, Cha 11.
STARTING ABILITY SCORES
Str 15, Con 14, Dex 10, Int 16, Wis 8, Cha 11.
AC: 22 Fort: 18 Reflex: 19 Will: 17
HP: 52 Surges: 9 Surge Value: 13
TRAINED SKILLS
Arcana +12, Athletics +11, Intimidate +8, Diplomacy +10
UNTRAINED SKILLS
Acrobatics +3, Bluff +3, Dungeoneering +2, Endurance +5, Heal +2, History +7, Insight +2, Nature +2, Perception +2, Religion +7, Stealth +3, Streetwise +3, Thievery +3
FEATS
Human: Hybrid Talent:
Swordmage Warding; See above
Level 1: Intelligent Blademaster:
Use Intelligence instead of Srength for MBAs; This makes your Op.Atks threatening and helps with "Vengeance is Mine" encounter power (Melee Basic Attacks)
Level 2: Light Blade Expertise:
+1 Atk with Light Blades; your warlord attacks definitely need this boost (it doesn't influence your implement attacks though ... but you could try and twist your DMs arm a bit ... you'd get away with it with me at least) and +1 dmg when you have CAdv which will mainly be when you flank the opponent. This is something you will want to achieve anyway, especially when you try and land your warlord powers; Atk bonus and dmg bonus scale with each tier of play.
Level 4: White Lotus Riposte:
Important disuasion for enemies to attack you. Only works with your swordmage at will powers. Basically, enemies you hit with your swordmage at will powers receive your INT mod. (+4) dmg if they attack you the round after you hit them. So, when you mark them with your Aegis they will want to hit, basically, to avoid the Mark penalty. If you have nailed them first with said powers then they receive 4 dmg, hit or miss. Riposte is also very Swashbucklery in my opinion!
Level 6: Improved Defenses:
As a hybrid defender/leader you're going to be front line (with a rapier), which means you'll be targeted alot. You need good defenses. This gives you +1 to ALL NADs (Non AC Defenses) and scales with tier. Boring but nearly unavoidable.
POWERS
Bonus At-Will Power: Sword Burst: (Swordmage);
Int vs Fort; Attack every enemy next to you. This applies White Lotus Riposte to every single enemy you hit
Hybrid at-will 1: Commander's Strike: (Warlord);
Have an ally attack for you; +4 DMG; Depends a lot on party make up, otherwise Intuitive Strike is another option as it attacks WILL and so your low STR won't be such a problem
Hybrid at-will 1: Booming Blade:
(Swordmage); INT vs AC weapon Atk; Applies White Lotus Riposte to target and if they move away from you you hit them again with a peal of thunder; This is a great power to hit an enemy that is marked by one of your allies with. If they go after them they get the extra damage. If they go after you they get -2 to hit you and Riposte dmg
Hybrid encounter 1: Vengeance is Mine:
(Warlord): You hit the enemy that hit you back with a MBA. You also yell at one of your allies 5 up to 5 squares away to get over and smack the guy as well. So imagine you've hit an enemy with Booming Blade and you have him marked with your Aegis. So he comes after you and hits. He take Riposte dmg and then you smack him back in the face, and an ally comes over, hopefully moving into flanking position, and smacks him as well! If he doesn't go after you, moving away, Boom, you hit him with thunder and he has -2 to his attacks ... and you can interruot him if he hits and reduce the damage by 7! Sweet combo!
Hybrid daily 1: Lamb to the Slaughter:
(Warlord) This one's usefulness depends on the group as well. If you have a barbarian, a fighter and ... I don't know ... a warlock with eldritch strike for example, it is sweet. Str vs Will weapon atk which really helps with your low Str accuracy issue and its Reliable. If you miss it's not wasted. You can Pull an enemy 5 towards you and up to 3 allies can get a free charge attack on it. If your party has a wizard, a bow ranger, and a sorceror ... you need to rethink this one ... Perhaps look at Fearless Rescue
Hybrid utility 2: Channeling Shield:
This basically allows you to use your Aegis of Shielding to interrupt a target that you don't have marked and reduce their damage by 7. You can use it on an ally or yourself. So even if they come after you because you have them marked, and hit you, you can still interrupt and reduce their damage 1/encounter; It gives you a small bonus next round as well
Hybrid encounter 3: Dimensional Vortex:
(Swordmage) Int vs Will; Interrupt an enemy attacking an ally and teleport them next to one of your other enemies who they accidently attack instead.
Hybrid daily 5: Swordmage Shielding Fire:
(Swordmage) Int vs Fort; Not only does this damage a creature up to 10 away, it marks them with your Aegis for the entire rest of the encounter, even if you miss. This means during that encounter you can have 2 enemies marked with your Aegis, which is awesome. Also every time you you reduce damage using your Aegis, the creatue takes the same amount of fire dmg.
Hybrid utility 6: Rousing Words:
An extra minor action Encounter Heal Power; this one allows 2 surges to be spent at once +5 hp. Your healing is still a far cry from a pure Warlord ... but you can still help a smart party get by when the chips are down.
ITEMS
Leather Armor, Rapier
Re: Where to find these Powers/Feats etc
To be honest your best bet and bang for your buck is to get a DDI subscription so you can get access to ALL the crunch at once via the Character Builder.