... have you honestly not seen/read enough anime/manga to know this???
-shama: ULTRA-cutesy version of -sama. Not a speech impediment, and so isn't restricted to cat's, nor will necessarily apply to all people.
Another great usage of -shama is in Ai Yori Aoshi. (Any of the Ai Ao Theatres where Aoi mentions Kaoru). Though, she's also noted as having cat-cuteness aspects too... hmmm...
Chen!(a vigorous "yes")Ran-shama went out...Ran-shama won't come back...Ran-shama won't come back...Yukari-sama! When is Ran-shama...Be a good kid and listen to Yukari-sama while I'm out.sleepingsh...If she never comes ba... back...Bwaaaaah!She's coming back soon!Really soonYukari-sama soothes herI have returned, Yukari-sama!Wipe your nose.That Ran...She was watching her from the shade...roll roll rollI wonder which one it is that can't stand to be alone.