How about...

#!/usr/bin/perl -w
use strict;

my $string = "foo.bar.blah.di.doh";

print "string: $string\n";

my @string;

@string = rev_split('.',$string,2);
print join(', ',@string)."\n";

@string = rev_split('.',$string,3);
print join(', ',@string)."\n";

@string = rev_split('.',$string,4);
print join(', ',@string)."\n";

$string = "foo:bar:blah:di:doh";

print "string: $string\n";

@string = rev_split(':',$string,3);
print join(', ',@string)."\n";

sub rev_split{
  my ($sep,$string,$cnt) = @_;
  $cnt--;
  my @string = split(/\Q$sep\E/,$string);
  $cnt = $#string if $#string < $cnt;
  my @array = ( join("$sep",@string[0..$#string-$cnt]), (@string[$#str
+ing-$cnt+1..$#string]) );
}

__END__

prints:
string: foo.bar.blah.di.doh
foo.bar.blah.di, doh
foo.bar.blah, di, doh
foo.bar, blah, di, doh
string: foo:bar:blah:di:doh
foo:bar:blah, di, doh
[download]

Update: modified so join pays attention to the separator..

Update2: added check to prevent returning more elements than we have.. thanks Enlil

Of course, with this implementation we can't use a regex as the split separator as join won't know what to join with..

cheers,

J