I'm in the process of working on something like that at the moment, largely due to my own issues with Heaven & Earth and the lack of any ability to remedy them myself... I'm not sticking strictly to any one ruleset, however, but instead mixing and matching bits of MgT "Hard Science" UWP generation, GURPS Space star and system generation, WBH planetary details, and a lot of hand-tweaking to get results that feel better to me.
I'm building it as a set of command-line tools to initially generate worlds/systems/subsectors with a webapp to browse the resulting data. There's no technical reason not to provide generation functions through the webapp (it would actually be very easy to add), that's just not necessary to the way that I'm using it myself, so I don't want to have to deal with deciding how I want to secure that functionality.
At this point, I think I've pretty much finalized generation of UWPs and base physical characteristics of worlds. Climate, society details, meta-game development (e.g., T4 Pocket Empires, MgT Dynasty, and/or SWN Factions), and, ideally, surface mapping are the major remaining pieces.
I'm happy to share the source (maybe I should even move it from my personal git server to github...), but it's not optimized for ease of installation, so you'd likely need to be fairly familiar with Perl to be able to run it.
