24 hour 2hr rings.

Marauder's Ring
Level 99, All jobs
Enchantment: Mighty Strikes

Pugilist's Ring
Level 99, All jobs
Enchantment: Hundred Fists

Thaumaturge's Ring
Level 99, All jobs
Enchantment: Manafont

Granted, some 2hrs are useless for other jobs like Astral Flow and Soul Voice, but some punishing combinations are certainly available.

A warrior with Mighty Strikes active and Hundred Fist enchantment or Meikyo Shisui enchantment.

Black Mage with Manafont active and a Chainspell enchantment.

I can smell the death.