So this one is a fun one to bake your noodle. It does have one odd point to it -- the mount is a lion instead of a horse, so not PFS play available -- but you could sub out the lion for a horse with little/ no problem. Just looking for some basic thoughts on the build and ideas.
Human (Qadira) Cavalier 8 (Order of the Sword)/ Duelist 4
HP: 12d10 + 20
BAB: +12 (+22/+17/+12 Scimitar (1d6+14/ 15-20) -- Charging Scimitar +26 (2d6+46/ 15-20 -- Challenge Charging Scimitar +29 (2d6+72/ 15-20))
Fort: + 7 (+11)
Ref: + 5 (+18)
Will: + 3 (+8)
AC: 26 (Touch 23, Flat 13) (generally aided by lion for 27)
Str 7 Dex 22(26) Con 12 Int 16(18) Wis 10 Cha 8
Trait: Charming
Racial Traits:
Eye for Talent
Heart of the Wilderness
Feats:
1 -- Weapon Finesse
2(b) -- Coordinated Manuevers
3 -- Dervish Dance
5 -- Dodge
6(b) -- Mobility
7 -- Mounted Combat
8(b) -- Ride by Attack
9 -- Boon Companion
11 -- Spirited Charge
12(b) -- Combat Reflexes
Skills
Perform (+14)
Acrobatics (+23)
Perception (+15)
Sense Motive (+17)
Knowledge(nobility) (+19)
Diplomacy (+14)
Ride (+23)
Equipment: +2 Keen Scimitar, +3 Bracers of Armor, +3 Cloak of Resistance, +4 Belt of Dex, +2 Headband of Int(Knowledge(local)), 2,650 gp
Lion
Str 27(29) Dex 19(21) Con 18(20) Int 3 Wis 15 Cha 10
HP: 10d10+50 (110 hp)
BAB: +7 (+14 Bite (1d8+14)/Claw (1d6+14)/Claw (1d6+14)-- +16 charge Bite/Claw/Claw/Rake (1d6+14)/Rake (1d6+14))
Fort: +7 (+15)
Ref: +7 (+15)
Will: +3 (+8)
AC: 31 (Touch 15 Flat Footed 26)
Feats:
Combat Reflexes
Power Attack
Body Guard
In Harm's Way
Enforcer
Skills:
Perception 1 (+6/+10)
Acrobatics 1 (+9)
Intimidate 8 (+11)
Equipment: +1 Merciful Amulet of the Mighty Fist, +2 Large Studded Leather barding, +2 Belt of perfection, + 3 Cloak of Resistance (saddle blanket), Legbands of the Zephyr