You could use the same technique but clobber a temporary array instead...

my @devices =
  grep { defined($_ = parse_node($_)) }
  my @tmp = @nodes;
[download]

Or you could use map:

my @devices =
  map { my $x; defined($x=parse_node($_)) ? $x : () }
  @nodes;
[download]

If parse_node was written to return the empty list in cases of failure (rather than returning the scalar undef), then it would just be:

my @devices = map { parse_node($_) } @nodes;
[download]