Here is the batch file I used after spending many frustrating hours in the powershell thread. Note that I have a custom install directory and not the default one. Real easy to change quickly in notepad with find and replace.

Code:
;Run this as an administrator

md c:\!Games\wow1

mklink /d c:\!Games\wow1\Data "c:\!Games\world of warcraft\Data"
mklink /d c:\!Games\wow1\Cache "c:\!Games\world of warcraft\Cache"

md c:\!Games\wow1\Errors

mklink /d c:\!Games\wow1\Interface "c:\!Games\world of warcraft\Interface"

md c:\!Games\wow1\Logs
md c:\!Games\wow1\WTF

mklink "c:\!Games\wow1\BackgroundDownloader.exe" "c:\!Games\world of warcraft\BackgroundDownloader.exe"
mklink "c:\!Games\wow1\Burning Crusade Install Log.html" "c:\!Games\world of warcraft\Burning Crusade Install Log.html"
mklink "c:\!Games\wow1\dbghelp.dll" "c:\!Games\world of warcraft\dbghelp.dll"
mklink "c:\!Games\wow1\DivxDecoder.dll" "c:\!Games\world of warcraft\DivxDecoder.dll"
mklink "c:\!Games\wow1\ijl15.dll" "c:\!Games\world of warcraft\ijl15.dll"

copy "c:\!Games\world of warcraft\Launcher.exe" c:\!Games\wow1\Launcher.exe

mklink "c:\!Games\wow1\Patch.html" "c:\!Games\world of warcraft\Patch.html"
mklink "c:\!Games\wow1\Patch.txt" "c:\!Games\world of warcraft\Patch.txt"
mklink "c:\!Games\wow1\realmlist.wtf" "c:\!Games\world of warcraft\realmlist.wtf"
mklink "c:\!Games\wow1\Repair.exe" "c:\!Games\world of warcraft\Repair.exe"
mklink "c:\!Games\wow1\Scan.dll" "c:\!Games\world of warcraft\Scan.dll"
mklink "c:\!Games\wow1\unicows.dll" "c:\!Games\world of warcraft\unicows.dll"
mklink "c:\!Games\wow1\World of Warcraft Install Log.html" "c:\!Games\world of warcraft\World of Warcraft Install Log.html"
mklink "c:\!Games\wow1\Wow.exe" "c:\!Games\world of warcraft\Wow.exe"
mklink "c:\!Games\wow1\WowError.exe" "c:\!Games\world of warcraft\WowError.exe"


;Syntax and definitions
;mklink [[/D] | [/H] | [/J]] link target
;/D – Creates a directory symbolic link. Default is a file symbolic link.
;/H – Creates a hard link instead of a symbolic link.
;/J – Creates a Directory Junction.
;link – Specifies the new symbolic link name.
;target – Specifies the path (relative or absolute) that the new link refers to.
;
;Just like ordinary files and folders, del and rmdir can be used to delete the 
;symbolic links to files and directories respectively.
;To delete symbolic link to a file, the following command line syntax can be used:
;del filename
;
;To delete symbolic link to a folder, the following command line syntax can be used:
;rmdir directoryname
;directoryname – Specifies the name of the folder/symbolic link to be deleted
;
;Supposedly (I have not tested this yet) in widows vista, windows explorer can be used to delete 
;the created directories safely when it is time to redo the links after an update
At the moment I run all my characters in 2 person teams, so I run this twice, I just open notepad and do a find and replace of wow1 with wow2 to make the second copy. After that I copy the WTF folders from the 2 original accounts. I imagine that in the future I will need to backup the wtf folders after updating the main wow to a new location when I go to delete these wow1 and wow2 directories then copy them back. Have not went thru an update yet.

Also, the clone copies (wow1 and wow2) are the 2 that I play from. since both are using the same addons folder, just have your slave toons unselect the addons you dont want them to run. I.E. wow1 runs alot more addons than wow2 does in my case since my main of each pair is on wow1.

EDIT July 17, 2009
If you have your accounts merged into a Battlenet account you need to add the following line:
mklink "c:\!Games\wow1\Battle.net.dll" "c:\!Games\world of warcraft\Battle.net.dll"