I've had two DSA602s on top of one of mine, with no concerns at all
(Anything to avoid wrangling a 602 onto a bench, they're >30kg and quite
big...) That sloping one I posted is much flimsier than usual, it's just
bent 1.2mm? sheet, but proper racks have borderline girders inside, and
castors to cope with a rack full of servers and a UPS.
Even the flimsy ones are pretty sturdy, and they stiffen up further with a
couple of shelves bolted to front & back rails.
Obviously, shipping racks is even worse than shipping proper scope carts,
but they may be easier to source locally.