I've been working on a "semi-alternate" setting. This means, the OTU is as it is, but I've added a new region: the Orion OB1 Association (which also exists in the real world).
It's a region of giant blue stars where there are hardly any (though there are some) solid worlds, just some gas giants and belts, belts, belts and belts, often more than seven per system. Belting is, of course, a common career in this region the size of the Imperium. The most important systems are located by stars visible from Terra (Rigel, Mintaka, Alnitak, and basically every other star in the appropriate distance range from http://en.wikipedia.org/wiki/List_of_stars_in_Orion
). There are many client states of the M'norr Republic, a mysterious outside force of which strange bases have been found along the spinward side of Charted Space. No-one in the Imperium knows quite where it is... or how big it is... or quite what TL...
Here's some external links:
What's your feedback on this in-progress setting?