The terms of cloning implied by AOTC is that the original host's memories cannot be transplanted into the clone's mind. I say that because Jango Fett had obvious combat skills while his clones had to be trained.
That being the case, it begs the question of why the Emperor would clone himself. He, Emperor Prime for like of a better description, would still die. Sure, the Emperor's clone would rise up and take over... but it wouldn't be Palpatine Prime doing it, just someone who looks like him, has a similar array of powers and none of his life experiences or memories.
Why would the Emperor bother since (as far as he knows) Sith hegemony of the galaxy will continue in the form of his Sith apprentice taking his place as ruler?
If I recall the terms of DE correctly (and honestly the idea of cloning the Emperor is so awful that I've never been able to even entertain the idea so I've never read all of DE), a host's memories can be implanted into a clone. If so, Palpatine would be risking himself. What if a clone should escape/prematurely be released from where ever clones are grown? Now Palpatine will be faced dealing with a Sith literally every bit as cunning, intelligent and powerful as himself.
What do you suppose the odds are that an escaped Palpatine clone would want to overthrow Palpatine Prime and install himself as the new Emperor? Being a Sith is treacherous business, after all.
End of the day, I can't envision Palpatine cloning himself under any circumstance.
That stuff aside, a Palpatine clone completely defeats the purpose of Vader's sacrifice.