I've just bought the "Making of" ROTS book and it has a part where Lucas originally wanted Dooku to be responsible for Shmis death and that Sidious was behind it all the time. It also mentions that Sidious created Anakin through the midichlorians.
I personally would have hated these ideas as it makes Anakins turn to the darkside too easy. What do you think?
I just mentioned this in the 'Evel Pale Bald Chick" thread, but IIRC, Shmi's kidnapping was originally to be done by Aurra Sing, who was hired by either Dooku or Sidious.
Also, Sidious using the midi-chlorians to create Anakin? I've thought about that one for a long time. Explains the whole virgin birth deal, but would totally confuse an audience.
But I think it's not a too easy deal. It would show how deeply involved Sidious would go to influence Skywalker.