This was very early stuff, and hasn't been repeated to my knowledge. Warhounds were a certain type of packhunting mammal
Things like Cybermastiffs are certainly still using imprints, Kal Jericho's Mastiff Wotan is essentially a well trained police dog with greater than average intelligence made out of steel.
Gun-servitors in the form of doggies with back mounted gun systems exist as well, cybernetic Hawks with taser claws, as well as fully organic cyber versions.
Titan AI's, Warlords in particular are still described as stubborn and aggressive, but older titans often have remnants of the previous Princeps floating around the system, and these contribute to the whole.
the Titan graphic novel has the best example of this, with Maccabee hanging around until he suicides to cause some Nids psychic feedback trauma.
If the Omnissiah actually does exist as a seperate entity to the Emperor or the Dragon, its possible that Vaul might have represented the Eldar aspect of such a being, bearing in mind Xenologies hints that "gods" is a fairly broad term in 40k, with C'tan, the various Old One races, artificially created beings etc all being included.[Bullshitting]Might Vaul the the Omnissiah?[/Bullshitting]