I'd agree on 600lbs. The internet standards can be a little unrealistic, and I kind of lumped your (flipcollar) response into it. One of the 275'ers in my gym hit 605 in the meet, and it was a really big deal...and our gym has a lot of pro strongman and elite powerlifters.
When I said, "not a problem" I meant that performing the lift with good form, with a belt give this SHW fat bastard no problems. On my worst, most bloated achy day-cause-I-am-old by some standards, I can still do it comfortably, and every time.
I should also have said that my training is more strongman focused, so deadlift is important, but it almost an accessory movement. I don't max on it very often, because through events I work my posterior chain every time I am in the gym. I think with focus and based on the 445 lift (the feels) I think 500 is attainable in the short term with some focus, and 600 is a realistic goal for 2016.