Actually 5X5's amount to only 25 reps total. And with the bonus of having a rest period between each of those 5 reps. Which should be a piece of cake for experienced lifters, even with 400-500lb sets. If you require 1 to 2 weeks to recover from those 25 total reps than you may want to adjust your training methods.
Take a hint from most PL'ers and not go to failure every set of Dl's (or anything else for that matter). Do not force out max effort reps, even on the last set of that lift. If you feel that you could get that last rep with max all out effort, do not. Stop at least one or maybe two reps away from that. If steady progress in muscle mass and strength is the goal than experiment with this style of training for a while and you be the judge as to how your body responds.
You are training the CNS (which needs not be taken beyond it's limits of recovery abilities after every workout) as much as you are the muscles of the body. And as we all know, the CNS is the key for recovery from each training session. And in return, allowing progressive gains in muscle mass and strength. If all thing being equal with smart workouts, good diet and proper recovery time, progress should be a steady part of anyones training goals. And than those 25 total rep DL become so much more easy to handle.
If the back seems to be taking too much of a beating from any DL workout (even a moderate one) than you may want to change you lifting mechanics. Something may be wrong with your lifting style or you have adopted bad lifting habits along the way. Or, which a few people overlook, the Dl is not really meant for their body type no matter what they do.
I get lots of post/E-mail about training style (not always on GetBig). And also video's showing a persons DL (and squat) form which are mostly disasters ready to happen. Do not know why they or their train Bud's can not see that. Main problem being, not squating low enough at the start of the lift and not keeping the lower back straight and in line with the lift. Too much bending forward losing the center line of power and putting the body in a crap position for the pull. Good Luck.