This was an effort of mine posted over on the House Rules forum (with some refinements from the other commenters).

After breaking down and picking up a PHB from the local bookstore last night (one of the late-adopter guys at the table will get a present when my Amazon order shows up) and trying to convert an Archivist PC from a PBP game that I rather liked (Khalia ir'Indari, I decided that although I could make a fairly respectable version of her as a Cleric, it wasn't quite right. So here's some hasty early morning scribbling...

Archivist

as cleric, except as noted

Key Abilities: Intelligence, Charisma
Armor profs: cloth, leather
Hit Points at 1st Level: 10 + Con score
Hit Points per Level Gained: 4

Trained Skills: Arcana, Religion. From the class skills list below, choose three more trained skills at 1st level.
Class Skills: Arcana, Diplomacy, Dungeoneering, Heal, History, Perception, Religion, Streetwise

Class features: Dark Knowledge, Healing Word, Ritual Casting, Prayerbook

Dark Knowledge - once per encouncter, an archivist can draw upon her expansive knowledge of monsters, granting her allies benefits against the creatures they face

Dark Knowledge attacks often are [Knowledge Skill] vs. defense.
[Knowledge Skill] is determined by creature type.
arcana - elemental, fey, shadow
dungeoneering - aberrant
nature - natural
religion - immortal or undead

Dark Knowledge: Tactics Archivist Feature
You draw on your extensive knowledge of creatures of the foe's type in order to advise your allies on how best to defeat it.
Daily * Divine
Standard Action Area: Burst 3 within 10 squares
Attack: [Knowledge Skill] vs. Will
Hit: Until the end of the encounter, your allies gain +1 power bonus to hit members of a specific type of creature within the area of effect
At 11th level, this bonus increases to +2. At 21st level, this bonus increases to +3

Dark Knowledge: Puissance Archivist Feature
With a quick word, you tell your allies you to avoid the foe's attacks.
Encounter * Divine
Minor Action Ranged: 10
Attack: [Knowledge Skill] vs. Will
Hit: Your allies gain +1 power bonus to defenses against a specific type of creature within the area of effect until the end of your next turn. At 11th level, this bonus increases to +2. At 21st level, this bonus increases to +3.

Prayerbook - as per a wizard's spellbook, except that it functions for prayers, not spells; feats and magic items which affect spellbooks affect prayerbooks, and magic items that can be used as spellbooks can be used as prayerbooks (this feature isn't very useful with just PH1; as more divine prayers become available, this will become more useful)

Powers - An archivist can use Intelligence instead of Wisdom for for all Cleric powers, but does not gain access to powers with the weapon keyword. An archivist can also use the wizard's Utility powers, though they count as prayers for an archivist.

New Feats
(heroic tier)
Dark Knowledge: Foe's Weakness
Prerequisite: Dark Knowledge class feature.
You gain the use of Foe's Weakness as a Dark Knowledge ability.

Dark Knowledge: Foe's Weakness
You learn any vulnerabilities the target has and make an immediate attack, exploiting this knowledge.
Prerequisite: You must have Knowledge skill training in the skill corresponding with the creature's type to use this power.
Encounter * Divine
Standard Action Ranged: 10
Target: One creature
Attack: INT vs. AC
Effect: Learn one vulnerability of the target. Until the end of your next turn, any ally exploiting the creature's vulnerability inflicts an addition 1d6 damage.
Hit: 1d10 + INT damage, plus if you exploit the creature's vulnerability with the appropriate damage type, the creature is dazed until the end of your next turn.
Miss: The creature isn't dazed and takes half damage. However, until the end of your next turn, any ally exploiting the creature's vulnerability inflicts an addition 1d6 damage.

(paragon tier)
Dark Knowledge: Dread Secret
Prerequisite: Dark Knowledge class feature.
You gain the use of Dread Secret as a Dark Knowledge ability.

Dark Knowledge: Dread Secret
Every creature has a secret it wishes were known to none. But the Archivist knows.
Prerequisite: You must have Knowledge skill training in the skill corresponding with the creature's type to use this power.
Daily * Divine
Standard Action Ranged: 10
Target: One creature
Attack: INT vs. Will
Effect: Learn the darkest secret of the target. Until the end of your next turn, the target is Stunned.
Hit: 2d8 + INT damage.
Miss: The creature takes half damage.

Dark Knowledge: Foreknowledge
Prerequisite: Dark Knowledge class feature.
You gain the use of Foreknowledge as a Dark Knowledge ability.

Dark Knowledge: Foreknowledge
A master archivist often can predict the moves of her enemies almost perfectly, and act on this information.
Prerequisite: You must have Knowledge skill training in the skill corresponding with the creature's type to use this power.
Daily * Divine
Standard Action Ranged: burst 2 within 10 squares
Target: All creatures of one type in area of effect
Attack: INT vs. Will
Hit: You anticipate the next attacks the target will make. Until the end of the encounter, your allies gain a +3 bonus to AC vs. that target.
Miss: Your knowledge of the target is less complete; you only provide a +1 bonus to AC.

drothgery