I had a conversation with someone recently who said the Emperor had someone try to clone Horus Lupercal, but there was no soul to put in the body as Horus has been totally destroyed, which my associate said just made The Emperor angry (I assume the person attempting to clone Horus knew by psychic communication?) On further conversation it was revealed it would be possible for the cabal to travel back in time and fetch Horus from the past, back before he was destroyed; however, she indicated that even if they knew it is The Will Of The Emperor they are still disinclined to do so as they have gotten used to hunting Chaos (and still consider Horus to have fallen to The Ruinous Powers???) and would not follow even a direct command from their Emperor to do so.
How much of the above is canon? Are people inclined to believe the truth of it?
(Footnote: Odd question, perhaps, but if Horus Lupercal were to be brought back, could something be done with The Enunica to bind Horus until such a time as He could be freed from the grip of Chaos?)