They haven't done any 'recorded' covers, unless they are rare/ extremely hard to get bootlegs.....
I remember at one point someone saying that Opeth were 'seeling-out' by doing cover songs, but when you think about it, they've done far lass covers than your average metal band (IE: 2)
I really wish they'd do a Black Sabbath cover though, that would be sweet!!!:hotjump: (For Nativity In Black III Perhaps!?)