R. Scott Bakker has held an Ask Me Anything session on Reddit and spilled some beans about his plans moving forwards, with The Unholy Consult (the final book in his Aspect-Emperor series) having been published last month.
SPOILERS FOR THE UNHOLY CONSULT FOLLOW:
The big news is that work is underway on the third and concluding arc in the Second Apocalypse saga. This sub-series will be called The No-God, which is interesting as it breaks the pattern of naming for the first two series (The Prince of Nothing and The Aspect-Emperor). The current plan is for a duology, but an expansion to a trilogy is entirely possible.
Scott doesn't have a name for the individual books in the series yet, not a clear idea of when they might be published. He also doesn't have a publishing deal yet, which may be contingent on how well The Unholy Consult does for Overlook and Orbit. He did confirm that the third series commences just a few weeks after the cataclysmic events at Golgotterath in The Unholy Consult and unfolds from there.