If you want the players to think "that is really impressive" or "why aren't we running?", stick your Wizard's ego in a Greater Stone Golem (42HD, magic immune, DR10/adamantine, CR16).
If you just want a CR14 Wizard, here you go. Feel free to substitute 1 level for Archmage, choose Arcane Reach or Arcane Fire. Gave him a little extra gold. Did not "prepare" spells from having a high INT score. Also, feel free to use the point buy system for stats, which would give him higher INT, but lower CON.
Unknown, Male Dwarf, Hill Wiz14: CR 14; Medium Humanoid (Dwarf); HD 14d4+42(Wizard) ; hp 83; Init +2; Spd 20; AC:28 (Flatfooted:26 Touch:15); Atk +6/1 base melee, +9/4 base ranged; SQ: +1 Attack vs. Orcs and Goblinoids, +2 Appraise (Stone and Metal Items), +2 Craft (Stone and Metal Items), +2 Saves vs. Poison, +2 Saves vs. Spells and Spell-like Effects, +4 Dodge Bonus to AC vs. Giants, Darkvision (Ex): 60 ft., Stability (Ex), Stonecunning (Ex), Weapon Familiarity (Ex); AL LG; SV Fort +7, Ref +6, Will +9; STR 8, DEX 14, CON 17, INT 19, WIS 10, CHA 10.
Skills: Concentration +18, Craft (Armorsmithing) +16, Craft (Blacksmithing) +4, Craft (Stonemasonry) +4, Craft (Weaponsmithing) +4, Decipher Script +13, Diplomacy +3, Knowledge (Arcana) +17, Profession (Miner) +2, Spellcraft +20, Swim +0.
Feats: Craft Wand, Extend Spell, Maximize Spell, Scribe Scroll, Skill Focus: Spellcraft, Spell Focus: Divination, Spell Focus: Evocation, Still Spell.
Spells Known (Wiz 4/5/5/5/5/3/3/2): 0 -- Acid Splash, Arcane Mark, Dancing Lights, Daze, Detect Magic, Detect Poison, Disrupt Undead, Flare, Ghost Sound, Light, Mage Hand, Mending, Message, Open/Close, Prestidigitation, Ray of Frost, Read Magic, Resistance, Touch of Fatigue; 1st -- Chill Touch, Comprehend Languages, Detect Secret Doors, Disguise Self, Enlarge Person, Grease, Identify, Mage Armor, Magic Weapon, Obscuring Mist, Ray of Enfeeblement, Reduce Person, Shield, Silent Image, Sleep, True Strike; 2nd -- Blur, Glitterdust, Invisibility, Melf`s Acid Arrow, Protection from Arrows, Scorching Ray, See Invisibility, Shatter, Tasha`s Hideous Laughter, Touch of Idiocy, Web; 3rd -- Blink, Clairaudience/Clairvoyance, Daylight, Deep Slumber, Dispel Magic, Fireball, Fly, Gaseous Form, Hold Person, Major Image, Nondetection, Ray of Exhaustion, Water Breathing; 4th -- Contagion, Dimension Door, Enervation, Evard`s Black Tentacles, Fear, Polymorph, Summon Monster IV, Wall of Ice; 5th -- Cloudkill, Cone of Cold, Dismissal, Magic Jar, Permanency, Planar Binding, Lesser, Summon Monster V, Wall of Force; 6th -- Antimagic Field, Bull`s Strength, Mass, Contingency, Disintegrate, Dispel Magic, Greater, Planar Binding, Summon Monster VI, True Seeing; 7th -- Delayed Blast Fireball, Ethereal Jaunt, Finger of Death, Forcecage, Reverse Gravity, Summon Monster VII, Symbol of Stunning.
Spells Prepared (Wiz 4/5/5/5/5/3/3/2): 0 - Light, Read Magic x2, Touch of Fatigue; 1st - Chill Touch, Enlarge Person, Grease, Reduce Person, True Strike; 2nd - Invisibility, Melf`s Acid Arrow, Protection from Arrows, Tasha`s Hideous Laughter, Web; 3rd - Blink, Dispel Magic x2, Fly x2; 4th - Contagion, Dimension Door, Enervation, Evard`s Black Tentacles, Polymorph, Wall of Ice; 5th - Cloudkill, Summon Monster V, Wall of Force; 6th -- Disintegrate, True Seeing; 7th - Reverse Gravity, Summon Monster VII.
Possessions:
Armor: Mithral Chain shirt, Twilight (2,250 gp).
Magic: Ring: Protection +3 (18,000 gp); Ring: Blinking (27,000 gp); Wondrous: Amulet of Natural Armor +4 (32,000 gp); Wondrous: Bracers of Armor +5 (25,000 gp); Wondrous: Headband of Intellect +4 (16,000 gp); Wondrous: Ioun Stone, Pink [Rhomboid] (8,000 gp); Potion: Fly (5) (750 gp); Rod: Metamagic, Silent (11,000 gp); Rod: Metamagic, Maximize (54,000 gp); Rod: Cancellation (11,000 gp).
Animal, Lizard, Male Animal, Lizard : CR 1/6; Tiny Animal ; HD 14d8 ( Animal) ; hp 41; Init + 2; Spd 20, Climb 20; AC 21; Atk + 5 base melee, + 11 base ranged; +11 ( 1d4-4, Bite ); SQ: Low-light Vision (Ex); AL N; SV Fort + 4, Ref + 6, Will + 9; STR 3, DEX 15, CON 10, INT 12, WIS 11, CHA 2.
Skills: Balance +10, Climb +6, Concentration +18, Diplomacy +3, Hide +10, Listen +3, Spot +3, Swim +0.
Feats: Alertness, Weapon Finesse.
A Rat is fine too.
Animal, Rat, Male Animal, Rat : CR 1/8; Tiny Animal ; HD 14d8 ( Animal) ; hp 41; Init + 2; Spd 15, Climb 15; AC 21; Atk + 5 base melee, + 11 base ranged; +11 ( 1d3-4, Bite ); SQ: Scent (Ex), Low-light Vision (Ex); AL N; SV Fort + 4, Ref + 6, Will + 10; STR 2, DEX 15, CON 10, INT 12, WIS 12, CHA 2.
Skills: Balance +10, Climb +12, Concentration +18, Diplomacy +3, Hide +14, Move Silently +10, Swim +10.
Feats: Weapon Finesse.
Feel free to change anything.