And here's a necromancer. The numbers are probably a bit off; I'm still adjusting my spreadsheet. Basically, started with a level 20 human, slammed the Wizard template on him, then the Lich template, then made him a Solo.
Evil Necromancer Lich (Human Wizard) Level 20 Solo Controller
Medium Undead Humanoid
Initiative +11 Senses: Perception 14, Darkvision
HP 870, Bloodied 435, Regeneration 10
Necromantic Aura 5 (take 5 necrotic damage)
AC 39, Fortitude 37, Reflex 37, Will 41
Resistances:Immune disease, poison
Saving Throws +2
Action Points 2
Speed 6

Melee Staff With Creepy Skull On End +25 vs. AC, 3d6+8 and ongoing 10 necrotic damage, save ends
Spells (with appropriate names)
Necrotic Flame (Scorching Burst) (AW)
Dust To Dust (Disintegrate) (D)
Wall Of Bones (Wall of Ice) (E)
Forlorn Encystment (Ice Tomb) (E)
Displacement (U)
Arcane Gate (U)
Spellmaster: Regain an expended encounter power, recharge
Necrotic Master: Can convert any damage to necrotic
Skills: Arcana +19, Religion +19
Rituals Known: Raise Undead Army
Strength 12 (+1/+11)
Constitution 14 (+2/+12)
Dexterity 12 (+1/+11)
Intelligence 19 (+4/+14)
Wisdom 18 (+4/+14)
Charisma 19 (+4/+14)
EDIT: Honestly, he'd be more fun just built from scratch, I think, using the class templates as a guideline but with purely unique abilities. 4e lets you do that; might as well get the most out of it.