This script will allow you to effectively hard link a directory. It reproduces the directory structure of the source in the destination and then recursively hard links all the files from the source to the corresponding location in the destination. If you've ever wanted to hard link a folder, this produces the results you want.

lndir.sh

#!/bin/bash
oldifs=$IFS
IFS='
'
[ $# -ne 2 ] && { echo "Usage: $0 sourceDirectory destinationDirectory" ; exit 1; }
[ ! -d "$1" ] && { echo "$1 is not a valid directory"; exit 1; }
[ ! -d "$2" ] && { mkdir -p "$2"; }
src=$(cd "$1" ; pwd)
dst=$(cd "$2" ; pwd)
find "$src" -type d |
while read dir; do
        mkdir -p "$dst${dir#$src}"
done

find "$src" -type f -o -type l |
while read src_f; do
        dst_f="$dst${src_f#$src}"
        ln "$src_f" "$dst_f"
done
IFS=$oldifs

As of reading this, I'm under the impression that this does the same thing as:
cp -lR
Please correct me if I'm wrong.

@wenzelie hard links do not require the space. it creates a inode pointer to the same data.