I've implemented atmospheric scattering as described by Sean O'Neil, with some modifications and endless tweaking. I'm still not quite satisfied, though, but I'll return to it later.
Meanwhile the other two lethargic programmers are presently awakened too.
Angrypig is working on tree generator that will produce all levels of detail needed for tree&forest rendering, from detailed models through continuously simplified and increasingly unified models down to billboards.
Jonsky is modifying the toolchain used to process heightfield maps for the engine (currently used to process earth's elevation data - remapping and wavelet compression). This can be then used to create custom planets; in fact he is currently testing it with the heightfield map of Tolkien's Middle-earth. When we release a demo you will be able to fly over that fantasy planet, or land in Mordor
So if people are interested, we could release some flyable demo sometime in the near future, with the possibility to define your own world using the heightfield map patches, specifying elevations in some rougher resolution. Fractal algorithm computes the details, vegetation is placed by algorithm taking terrain properties into account. One thing still missing are the climatic maps so we could generate deserts and steppes and so on; but this one still requires some thinking.