Duster V is still a rare spawn around the enterence.
Duster X now only spawns once you turn in the report, he spawns down by the
tinkering merchant, and doesnt wander anymore, he just stands in place.
I did this quest once (and am waiting for Duster V to do it again) and got the
Bootstrutters Pack, 10slot backpack with 10% weight reduction..
A lot of the junk that you used to get for this quest (back when Dustre X was a
wandering rare spawn) can now also be gotten by turning in scrap metal from
rogues to Sanfryd Feathertop (who used to be called Sanfryd somethingelse).
Amongst the normal lanterns/shield junk you can also get gnomish glow rods, and
chunks of metal ore that look like balls instead of bricks...

Getting the duster report seems to be less common than it used to be as well - I
get the Red V report a lot more now, previously it was the other way around..