Well, exactly such a thing is what I have started in my SCAN project.
Look at http://squeak.heeg.de/ for some information. Basically, I want
to build a repository that stores versioned software components and
more, using digital signatures for authentication and integrity
checking. Much of it already exists on my Powerbook and will eventually
run on that squeak.heeg.de machine, but I currently have too little time
because I'm working full time in a customer project and have little
spare time to spend on SCAN.
I do think that my ideas on a repository are well thought out and will
provide a much better substrate for sharing and versioning than an
ad-hoc approach.
I would be rather disappointed if just a few weeks before I can start to
work full time on SCAN somebody came across and implemented something in
a hurry which provides only part of the SCAN functionality, but makes
introducing SCAN much harder because it's just there first.

So please, read that stuff at squeak.heeg.de, tell me what you think
about it, contribute your ideas and criticisms, but just don't rush for
a solution thats only a half-solution!

Cheers,
Hans-Martin