I don't like thrashing @_ because I'm weird, so how about something like this?

    my $aPush = sub { \@_ };
    my $av = [];
    for (my $index = 0;$index < @_; $index += 16) {
      my $length = $#_ - $index;
      $av = $aPush->(@$rv, ($_[$index][0],$_[$index+1][0],
              $_[$index+2][0],$_[$index+3][0],$_[$index+4][0],
              $_[$index+5][0],$_[$index+6][0],$_[$index+7][0],
              $_[$index+8][0],$_[$index+9][0],$_[$index+10][0],
              $_[$index+11][0],$_[$index+12][0],$_[$index+13][0],
              $_[$index+14][0],$_[$index+15][0]
                )[ 0..($length < 16 ? $length:15) ]
            );
    }
[download]

Update: After benchmarking this against what you have in the previous post, yours is definitely faster.