I checked on the username "Rajah*" as well phred, and came up with the same results as Lisa. However when I tried to register that name I got the response, "username already taken", just like you did.
I did go ahead and register the name "Rajah21" for your daughter and added the 29 "old posts" to that profile for her. (I'm sending you the login information via email.) If you prefer another name or have any other questions let me know!