This would be my take of a 11th level Gwendolyn. She was build as:
1st: swashbuckler
2nd: wizard
3-5: elf paragon
6-7: swashbuckler
8-11: bladesinger
She spent 66.000 gp on equipment, the standard wealth for a 11th level character.
Gwendolyn is a decent defensive mobile fighter and second rate arcane spellcaster.
Looking ahead the next feat would be arcane strike and then improved critical. The last three levels (18-20) would be either wizard or eldritch knight.
Lady Gwendilyn, Bladesinger of Varnaith Character level 11 (swashbuckler 3rd / wizard 1st / elven paragon 3rd / bladesinger 4th)
Medium humanoid (Sun elf)
Hit Dice: 3d10+7d8+1d4+33 (87 hp)
Initiative: +5
Speed: Move 40' (8 squares)
Armor Class: 21, 21 touch, 12 flat-footed
Base Attack/Grapple: +9/+11
Attack: Rapier melee +16 (1d6+9+1d6 electrical, 15-20/x2) or wand of magic missile (5d4+5)
Full Attack: Rapier melee +16/+11 (1d6+9+1d6 electrical, 15-20/x2) or wand of magic missile (5d4+5)
Space/Reach: 5 feet/5 feet
Special Attacks: Spells
Special Qualities: Bladesong style, lesser spellsong, song of celerity (2nd), insightful strike, racial immunity (sleep), low-light vision.
Saves: Fort +11, Ref +14, Will +9
Abilities: Str 15, Dex 20, Con 16, Int 24, Wis 12, Cha 11
Skills: Balance +15, Bluff +5, Climb +9, Concentration +12 (+16 combat casting), Diplomacy +8, Jump +20, Knowledge (arcane) +19, Listen +9, Perform (dancing) +2, Perform (singing) +2, Sense Motive +6, Spellcraft +19, Spot +11, Swim +5, Tumble +21
Feats: Dodge (1st), combat expertise (3rd), combat casting (6th), practised spellcaster (9th), weapon finesse (swashbuckler 1st), scribe scroll (wizard 1st), weapon focus - rapier (paragon 2nd)
Description: 4 feet 10 inches, 70 pounds, frail beauty, long raven dark hair, grey eyes, milky skin
COMBAT
Gwendolyn will at most times keep a mage armor spell up (Armor Class: 25, 25 touch, 16 flat-footed). If she expects that combat is imminent, she will cast shield as well (Armor Class: 29, 29 touch, 20 flat-footed).
In combat her focus will be to tie up dangerous attackers in melee. She will often use combat expertise to increase her already impressive AC (-5 attack bonus, +5 AC) even more and then attempt to weaken the foe with spells (ray of enfeeblement, hideous laughter, hold person, ghoul touch) before attacking in earnest.
If forced into ranged combat she will use her assortment of scrolls and wand to good effect.
Spells (Sp): DC to resist powers is 17 + spell level.
Spells memorized
0th: dancing lights, daze, ghost sound
1st: mage armor, shield, ray of enfeeblement*2, color spray
2nd: ghoul touch, protection from arrows, tasha's hideous laughter, glittedust
3rd: hold person, slow
Spells known
0th: all PHB spells
1st: mage armor, shield, shocking grasp, color spray, ray of enfeeblement, protection from evil, enlarge person
2nd: ghoul touch, protection from arrows, tasha's hideous laughter, glitterdust, resist energy, web, mirror image
3rd: displacement, hold person, vampiric touch, slow, haste, dispel magic, fly, lightning bolt
EQUIPMENT
Gloves of dexterity +2, Headband of intellect +2, Keen shocking rapier +1, Boots of striding and springing, Ring of protection +2, Cloak of protection +2, Ring of counterspells (dispel magic), Amulet of health +2, Wand of magic missile (9th), Various scrolls (at least 1 scroll of each spell known) and potions of 8.000 gp value.