Here is the link for Mighty Rage Potion
The info is exactly the same as the lesser version, which is Great Rage Potion
Mighty Rage potion requires level 46 and gives 45 to 75 rage and also increases strength by 60 for 20 seconds.
It requires 3 x Gromsblood and 1 x Crystal Vial
Not sure if this is the right place for this, but there you go.
*edit*
I think I had my links mixed up, but it appears to be fixed now. The only other error is on this page where it lists both potions (great and mighty rage) as having the same ingredients.
Edited, Jul 10th 2008 8:32am by jpaugh