I can deadlift just a smidge (20lbs or so, depending on the day) more than 440lbs.
Regardless of bodyweight.
I've done it at 215lbs, and at 275lbs (fat phase). More bodyweight has never done anything for increasing/decreasing my deadlift. I am officially maxed out on the lift and have been for several years. I have a long torso and shorter legs and arms, which makes me ill suited for the lift (great for squatting and benching though).
But I'm done heavy lifting for the most part. A couple of weeks ago I pulled 430 from the floor to see if I could still do it after a year or so of not trying. It felt real heavy, and I don't think I care to try it again.