i didn't see anything like this for chunking up the list. this way makes me warm and fuzzy...

@things = 'a'..'z';
print "#things", $/;
print "@things", $/;

$by = 5;
print "#by", $/;
print "$by", $/;

@extra = ('.') x $by - 1;

print "#extra", $/;
print "@extra", $/;

@padded_things = (@things, @extra);
print "#padded_things", $/;
print "@padded_things", $/;

print "#chunked", $/;
while ( (@chunk = splice @padded_things, 0, $by) == $by ) {
    print "@chunk", $/;
}
[download]

$ perl test.pl 
#things
a b c d e f g h i j k l m n o p q r s t u v w x y z
#by
5
#extra
. . . . 
#padded_things
a b c d e f g h i j k l m n o p q r s t u v w x y z  . . . .
#chunked
a b c d e
f g h i j
k l m n o
p q r s t
u v w x y
z . . . .