I thought I would post what I built based on my own insight and inspiration from this thread. It uses some modified items but should be pretty easy to understand. It fits in well with the background of my campaign as well:
CE Medium undead (incorporeal)
Init +15; Senses darkvision 60 ft., hear heartbeat; Perception +31
AC 26, touch 26, flat-footed 14 (+4 deflection, +11 Dex, +1 dodge)
hp 161 (19d8+76)
Fort +13, Ref +22, Will +25
Defensive Abilities incorporeal; Immune undead traits
Weaknesses sunlight powerlessness
Speed fly 60 ft. (perfect)
Melee incorporeal touch +26 (14d6 negative energy plus terror)
Special Attacks wail
Str —, Dex 32, Con —, Int 20, Wis 20, Cha 19
Base Atk +14; CMB +25; CMD 40
Feats Alertness, Combat Reflexes, Dodge, Improved Initiative, Iron Will, Lightning Reflexes, Mobility, Step Up, Weapon Focus (touch), Arcane Strike
Skills Fly +19, Perception +31, Sense Motive +7
Languages Common, Elven
Hear Heartbeat (Ex)
A banshee can sense the beating hearts of living creatures within 60 feet, as if it had the blindsight ability.
A creature damaged by the banshee’s touch attack must make a DC 23 Will save. Failure means that the victim cowers in fear for 1d3 rounds. If a target is protected against fear by a dispellable effect (such as heroes’ feast or mind blank), the banshee’s touch attempts to dispel one such effect with greater dispel magic (CL 14th). Negative energy damage caused by a banshee’s touch can only harm the living; it cannot heal undead. This is a mind-affecting fear effect. The save DC is Charisma-based.
Once per minute, a banshee may wail as a full-round action. The wail lasts until the beginning of her next turn. All creatures within 40 feet of the banshee when she begins her wail, as well as all creatures that end their turn within that radius, must make a DC 23 Fortitude save. (This save is only required once per wail.) Creatures under the effects of a fear effect take a –4 penalty on this save. Creatures that make their save are sickened for 1d6 rounds. Those that fail take 140 points of damage (as if affected by a CL 14 wail of the banshee). If a wailing banshee is damaged during a wail, she must make a Will save (DC 15 + damage taken) to maintain the wail; otherwise it ends. This is a sonic death effect. Banshee wails are supernaturally powerful, and penetrate the effect of any spell of 3rd level or lower that creates silence. The save DC is Charisma-based.
Banshee Necromancer Wizard
Power Over Undead, Grave Touch, Arcane School: Necromancy (Enchantment.Illusion barred), , Turn Undead (bonus), Command Undead (bonus), Scribe Scroll (bonus), Spell Focus: Necromancy (1st)
Spell Focus: Conjuration (3rd)
Craft Construct (bonus), Augment Summoning (5th)
Undead Master (7th)
Superior Summoning (9th)
Spell Specialization: Animate Dead (bonus)
Ghost Touch Staff of the Master (Necromancy)
Ghost Touch Wizard's Robes (as Sorcerer's Robe except it uses a Wizard's school ability
Grandfather’s Legacy (Level 14 Necromancer)
This pair of lexicons is covered in excellently preserved human skin, with an intricate lace of fingerbones forming the locks on the cover. A family seal has been embossed on the lower center of the cover, but flecks of gold leaf have begun to peel away, revealing that the embossed pattern in fact follows a faded tattoo on the skin itself. A third book appearing identical to the first two except being less substantial and made of shadowy material that doesn't seem completely there.
Protection The edges of the first three pages of each book are coated with potent Violet Venom poison (contact; save Fort DC 15; 1d3 Str and 1d3 Con; cure 2 saves).
Protection A series of three superior locks each augmented with arcane lock (DC 50) and a symbol of weakness (Fortitude DC 20) on the fourth page of each book.
The third book is less substantial and made of a shadowy smokey substance. It is actually a Ghost Touch book and is partially ethereal.
Protection Fire trap modified to inflict cold damage (Reflex DC 20) and 1 negative level (Fortitude DC 20) unless negative energy heals the opener.
Opposition schools Enchantment, illusion
Value 13,195 gp
7th—control undead S+, finger of death S+, symbol of weakness S, temporary resurrection s, summon monster 7
6th—acid fog, chain lightning, circle of death S+, create undead S+, summon monster 6, control water
5th—dismissal, wall of force, waves of fatigue s, siphon magic, unbreakable construct, summon monster 5, sonic thrust+, daywalker +, ghoul army+, mass repair undead, suffocation, vampiric shadow shield, hungry earth
4th—animate dead S+, bestow curse S, contagion S, enervation S, shadow projection S [APG], shout, wall of ice, fire trap, summon monster 4, resilient sphere
3rd—gentle repose S, halt undead S, lightning bolt, magic circle against good, nondetection, ray of exhaustion S, stinking cloud, vampiric touch s+, summon monster 3, ablative barrier, gloomblind bolts+, call the void, lesser animate dead+, symbol of exsanguination+, lesser animate dead+, vampiric touch, summon monster, haste
2nd—arcane lock, blindness S, darkness, false life S, obscure object, resist energy, scare S, summon swarm, protective penumbra+, blood transcription+, defending bone+, command undead+, pernicious poison, alter self, fox's cunning, steal breath+
1st—cause fear S, chill touch S, floating disk, restore corpse S [UM]+, hypnotism, obscuring mist, ray of enfeeblement S, sculpt corpse S [APG]+, shield, sleep, wave shield+, mage armor, mount, magic missle, decompose corpse+, repair undead+, crafter's fortune+
Spells marked with + are in the third book.
Breath of the Grave (Su) As a swift action, spend this boon’s effect to breathe a 15-foot cone of rotting stench. Creatures within the cone must succeed at a Fortitude saving throw (DC 10 + your highest caster level in a class that prepares spells) or be sickened for 1 round. This spends the boon. After this boon has been spent, you take a –4 penalty on Diplomacy and Stealth checks until you prepare spells again.
Maybe it will help someone else who needs to come up with a similar concept quickly.