[plt-scheme] Versioned development against Planet packages?

Hi folks,

Planet has got a lot of interesting packages on it. I would venture to
guess that some folks have already written code that references planet
libraries, directly on the planet server.

The development model with which I am most familiar is the notion of
having a "vendor" project in my version control system. As new
versions are released, they are imported into my copy of the project
as tags (as appropriate of course).

Does anyone take this approach with packages on planet?

What would be the easiest way to do something like this with packages on planet?

I've see that after installing a package you can grab it from the
cache, this would be one way to get to the release files.