A blurb for The Infernal City: An Elder Scrolls Novel on Waterstones.com (it has now been changed) has possibly confirmed that ‘The Elder Scrolls V’ is in the making. It says:
More here.«A novel that takes places forty-five years after the Oblivion Crisis, which is the story of The Elder Scrolls IV: Oblivion game and the expansion pack Shivering Isles. It partly bridges the gap for the next game, which is set 200 years after the Oblivion crisis.»