Please do Slayer Raining Blood or Angel of Death. And for something more out there Cannibal Corpse's Hammer Smashed Face has enough melodic elements I believe you could pull off, and you don't even need to worry about a solo! Or you could just do Celtic Frost or Immortal and barely do anything at all
What about RW-fying something from Grave Digger, like Excalibur. Both bands are from the German speed/power/heavy scene, but they sound absolutely different compared to each other, so this is supposed to be hard.