It does exist, and it's not really that hard to implement in 6.0.
This is called... a Linux Package Server.
Yep. I'm not writing this just because I'm a Linux user but because it simply worked so nicely and fast that it's (for a normal Windows Package Server user) unbelievable.
So, let's go back in time a little. I worked with engineering on the package info problem for a large customer of mine, with many PS falling out of synch issue (hence I mumbled about the getpackageinfo interface many a time before ).
Whilst I was testing the root causes of the problem on Windows I decided to test a Linux package server on a Sunday morning. This was after I had started a fresh test, clearing the package.xml and snapshot.xml from a Windows Package Server with ~1,500 packages. The Windows PS did not have so much work to do, but it was still laborious due to the PackageCodebase Cache crawl (I didn't explain this before, but suffice to say...