UPDATE: modified to deal with jumps larger than 1 back up the hierarchy.

Very nice puzzle. Here is my proposal: (it does not do the { inlist => [... bits, but they can be inserted where indicated)

use strict;
use warnings;
use Data::Dumper;

my %type = ( '*' => 'u', '#' => 'o' );

sub type { $type{ substr shift, -1 } }

my @lines = map { /([*#]*)(\d*)\s+(.*)/; $2?[$1,[$3,{value=>$2}]]:[$1,
+ $3] } <DATA>;
my @lists = ( [] );
my $lasttype = '';
my $lastitem = $lists[-1];
my @stack;

for (@lines) {
  my( $type, $item ) = @$_;
  if( not $type ) {
    push @lists, [];
    $lastitem = $lists[-1];
    $lasttype = '';
    @stack = ();
    next;
  }
  if( $type eq $lasttype ) {
    push @$lastitem, $item;
    next;
  }
  if( not $lasttype ) {
    push @$lastitem, type($type), [ $item ];
    $lastitem = $lastitem->[-1];
    $lasttype = $type;
    push @stack, [ $lastitem, $lasttype ];
    next;
  }
  if( length( $type ) > length( $lasttype ) ) { # modify this block fo
+r { inlist => [...
    push @stack, [ $lastitem, $lasttype ];
    $lastitem->[-1] = [ $lastitem->[-1], [ type($type), [$item] ] ];
    $lastitem = $lastitem->[-1]->[1]->[1];
    $lasttype = $type;
    next;
  }
  for( 1..(length( $lasttype ) - length( $type )) ) {
    ( $lastitem, $lasttype ) = @{ pop @stack };
  }
  push @$lastitem, $item;
}

print Dumper \@lists;

__DATA__
* list 1 unordered item 1
* list 1 unordered item 2
*# list 1 unordered item 2 ordered item 1
*# list 1 unordered item 2 ordered item 2
*# list 1 unordered item 2 ordered item 3
* list 1 unordered item 3
** list 1 unordered item unordered item 1
** list 1 unordered item unordered item 2
** list 1 unordered item unordered item 3
**# list 1 unordered item unordered item 3 ordered item 1
**# list 1 unordered item unordered item 3 ordered item 2
**# list 1 unordered item unordered item 3 ordered item 3
* list 1 unordered item 4

# list 2 ordered item 1
#3 list 2 ordered item 2
# list 2 ordered item 3
#* list 2 ordered item 3 unordered item 1
#* list 2 ordered item 3 unordered item 2
#* list 2 ordered item 3 unordered item 3
# list 2 ordered item 4
[download]

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