Is it possible to Clone (spell) a Simulacrum (spell)?
If slain, the Simulacrum-creature reverts back to snow &/or basic / simple components not suitable as flesh for this spell. A Clone would have to be cast whilst the host Simulacrum-creature were still 'alive'
The flesh of a Simulacrum-entity is not able to accept healing of any kind (magical, First Aid or rests). Instead the flesh must be repaired in a suitable laboratory at great cost. This implies the 'flesh' may be of some golem material (similar perhaps to Edward Scissorhands). As such, it may not be effectively cloned.
In short, even though a Simulacrum functions as a warm, living, breathing creature (given to starvation, dehydration, drowning, etc., just like the origin-target humanoid used for the spell), it may not really be alive.
If there is any documentation, advice or tweets for or against the cloning of simulacra, let us know.