Oh yeah, Opeth version of Mrs. Robinson "And here's to you, Mrs. Robinson, Jesus loves you more than you will know..." that'll just roll of Mike's tongue. Maybe he could do that song entirely in death vocals? Then, they can do Cecilia. That'll be great.
Actually, maybe they could do Mrs. Robinson, and modify the lyrics, y'know, "Opethize" them.
"And here's to you, Mrs. Robinson, tainted crestfallen dogmas in the moor... ooh ooh ooh... god bless you please, Mrs. Robinson, fall of Autumn over the moon-dogged lake... hey hey hey..."
Perhaps an entire best of the Bay City Rollers cover album? And I believe luke's Opeth Christmas mix suggestion is still on on the table...