High Level Cohort

[Vedic Wizard]

But then, he doesn't need an optimal cohort - he's playing a Wiz-7/Rogue-9/Fighter-8; the game doesn't really include optimization.

A little optimization is fine, but it's a very story based game, so I'll have to justify any class or combination of classes I select. Particularly niche builds will be hard to justify, as will classes that would look unkindly at the more nefarious activities that the character is involved with.

I agree druids can be really tough in combat at mid-low levels, but we've got a high level druid in the party and he's much more useful as a summoner/healer/support character than actually getting stuck in to combat. Most of the things we're fighting would take the damage he can dish out, then hit with everything and tear him to shreds.

 

[Drowbane]

What self respecting LE wouldn't want an army of undead?

An epic character of mine (LE, Fighter 8, Rogue 9, Wizard 7) has just acquired the leadership feat. With all the adjustments he can attract a 17th level cohort...

The important thing is that he should be able to contribute something in a party made-up of 22+ lvl characters...

A level 17 Cleric or Wizard (any straight caster) would contribute as much or more than your Fi 8 / Rog 9 / Wiz 7...

Does your party lack healing? Even if not, the a high level Cleric has alot to offer. Buffs (self and you), Healing (self, you, and emergency for others), Melee (after buffs), Blasting (I love Flame Strike)...

edit: If you want to go CHEESE...

Cohort
Human (?) Vampire (8) Class X / Master Vampire 1 (libris mortis)
Str ?
Dex ?
Con -
Int ?
Wis ?
Cha high as possible

Make full use of your Create Spawn abilities.
Assuming a fairly modest Cha of 30... your Vampire could have 29 HD worth of spawn. A handful of vampire spawn (3 at 4 HD each and one uber spawn... HD 17? (ECL 25)... who has his/her own spawn?).

My lvl 18 necro-type had (campaign on hiatus :/) an undead army through similiar means.

What? Its EPIC!