I am in strong agreement with the above post on Limited Wish and the Mother Cyst feat. Here is the sorcerer spell list I wound up going with for
this guy. The stuff in parenthesis is from magic items (I did go with the whole Rainment of the Four set), as well as a Runestaff with the following:
Runestaff3rd: Primal Instict (1xday 3x3x100=900)
5th: Dragonsight, Overland Flight (1xday each, 5x5x100x2=5000)
7th: Limited Wish and Necrotic Tumor 1xday each (7x7x200=9800 gp + 7x7x100=4900)
Total cost: 20600 gp
His CL is only 12, so he has to use Versatile Spellcaster to access the 7th level spells.
Spells known (Per day)0th (6): Detect Magic, No Light, Mage Hand, Dancing Lights, Prestidigitation, Launch Item, Caltrops, Ghost Sound, Message
1st (8): Silent Image, Nerveskitter, Grease, Lesser Orb of Acid, Mount, (Magic Missile 3xday), (Nerveskitter 3x as SLA)
2nd (8): Glitterdust, Alter Self, Toothed Tentacle, Kelgore's Grave Mist, Wings of Cover
3rd (9): Dispel Magic, Shrink Item, Shatterfloor, Greater Magic Weapon, (Primal Instinct 1xday, Fireball 2xday)
4th (8): Evard's Black Tentacles, Greater Mirror Image, Celerity, (Freedom of Movement 2xday)
5th (7): Magic Jar, Telekinesis, (Dragonsight 1xday, Overland Flight 1xday, Teleport 2xday)
6th (5): Superior Resistance
7th (0): (Limited Wish, Necrotic Cyst*)
*Other Necrotic Cyst spells not listed above, but he has access to them.
Overland Flight is a bit subobtimal, but I like the "flavor" of flying around without wings for him. Magic Jar was required for a PrC prereq. Toothed Tentacle is a decent spell if you share it with your familiar and have Knowledge Devotion (or other damage adders), but it could be replaced. I took Mount mostly for setting off traps, because it lasts longer than Summon Dead Monkey.