Piranha Games revealed MechWarrior 5: Clans today, a new stand alone MechWarrior game coming to PC, Xbox and PlayStation consoles next year. MechWarrior 5: Clans, while retaining the MechWarrior 5 designation, represents a transformative step forward in the MechWarrior 5 franchise. MechWarrior 5: Clans linear campaign will be an evolution of gameplay and storytelling in the MechWarrior series, experienced from the perspective of Clan Smoke Jaguar in the pivotal conflict known as the Clan Invasion starting in the year 3050.
They are indeed, to a degree, though it basically never comes up. There is an illustration of a Pleasure Circus in the A Time of War RPG companion book with a catgirl. I screenshotted my copy of the PDF here.
The mods are described on page 53, “functional tail and mobile ears”.