I can provide a savegame which will essentially give the mage 74 intel or 84 with a wonderers scroll. Amazing Items through the entire game, however I don't remember where I found every item. KBscanner might know that
Skull of death + 5
Usurers Ring + 5
Snake Ring of wisdom +5
Amulet of death + 5
Boots of the Mystic + 2
Dress of the Magess + 5
Dress of the Prinsess + 1
Silver Chain +1
Wizards Hat + 2
Dimpoma in Anti-Magic + 2
Scale Shield + 3
Archmages Staff +5
Ring of the Mind + 3 (permanent)
I never used this setup, since my companion was Moro, but I loaded a game and tried to visit Elenhel to see, how high it went. I guess only with a 2nd Dress of the Magess and it could get even higher, but 84 (with scroll) is pretty decent.
Other Notable Items:
Mask of Hate, Black Helmet, Crystal Helmet (Much better than +2 intel late game)
Twinkling Boots
Magician's Cape, Steam Armor.
Ancient Amulet, Banner of True Faith, Gladiator Sword
Shield of Recross