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 that the codebase cache was completely removed from the 7.x codebase). So I took on the trivial task of setting up a Package Server on a SuSe Linux VM I had on the network.
The agent was up and running quickly and after a quirk to allow the machine to appear on the PS Candidates (it didn't have a web-server and I didn't want to install one, so I faked it on the basic inventory roles table) I had the PS added to the installation policy.
I was checking the Windows package server status on the database server and was almost shocked when I noticed that the Linux PS had completely synchronized within a polling interval (I would happily say I checked the DB every 15 minutes, but it couldn't have been more than 30 in all cases).
Now considering the Linux PS configuration items it is very easy to work out why and how the 1.5GiB of data was replicated in a breeze: the PS Agent will use 5 concurrent processes to download packages, so even in the event of hitting a runaway package info request (a request that causes the server to take 5~10 minutes to complete) the agent won't get stuck and can continue working effectively!
So the only thing I can say is, well, that we no longer have Linux Package Server support in 7.0 and 7.1... which is probably why I held back this information (but in the end I think it's still good to share it).