I reckon I'd find it near impossible to play Lamb Of God's Redneck without being in a drop tuning. I don't really like playing in non standard tunings at all but in a cover band it's a necessary evil!
Saying that, all the Drop B stuff we play, I just use a 5 or 6 string in standard tuning. No dodgy stretching necessary, but then it is kids stuff like Slipknot mostly