Delft University publishes MSc thesis "The Design of a Stitched, High-dynamic Range CMOS Particle Sensor" by Jiaqi Zhu. The thesis presents a cooperative work with Caeleste. The DR extension is achieved by a dual-gain 6.5um pixel:
The sensor resolution is up to 150MP (12288 x 12288 pixel). No silicon results yet, but the tapeout was scheduled for May 2014.