Mr. Laser Beam wrote:
^ Yep. They had an episode called "Kilkenny Cats" ready to be written, but I don't think it ever made it out of the concept stage. Linky
From comments I've read over the years, "Kilkenny Cats" was pretty much a recycling of DS9's "The Abandoned", with a baby Kzinti being found and raised by the NX-01 crew.
I grew up assuming TAS was non-canon, so I'm VERY dubious about bringing anything from it into the live action series.
They've been referencing TAS since DS9, throughout ENT and even in TOS-R. ST'09 remade entire scenes from "Yesteryear", including Sarek's entire speech to young Spock about the path of logic (which was told to young Spock by the older Spock in the altered "Yesteryear" timeline, reciting what Sarek told him
when he was that age)
The Kzinti backstory (lifted straight from Niven's Known Space
universe) would have needed some tweaking to fit into the modern Trek timeline, though. And that's even if they could have reached an agreement with whoever owns the Kzinti (due to this, the Kzin have been renamed M'dok, Mirak and Kythari in licenced Trek novels, videogames and short stories over the years)