Ok, i give thee challenges three:
1.the easy one, vivaldi's four seasons
2. medium difficulty, Mr.Sandman by Pat Ballard
3. hard, this is technically a metal cove of another metal song, but this is a harder version, anyways, find The death metal version of Aces high from Iron maiden that have a Bagpipe solo.
and a bonus round: which song from what band copies the instrumental intro to "somebody to love" by Queen, hint; the band is fronted by one of the pioneers of Power Metal
EDIT: all of these exist BTW, i have them on my computer