Does anyone know of ways to assist managing slide collateral in PowerPoint,
or via some tool integrated with PowerPoint.  

We develop many different presentations for different audiences, but
frequently use the same slides.  This means a lot of cut+paste, many
different versions of presentations that combine different sets of the same
slides.  This leads to headaches in updating all slide decks when a slide
needs updating, etc.

Ideally, we'd like a way to:

- Be able to select slides from a central archive, order them, publish them.
- Be able to update a slide in the archive, automatically updating decks
that include
 the slide
- Be able to change the master easily, automatically changing how the
published deck appears.
- Be able to see the date when the slide was changed, have some version
control on it.

Any ideas, experiences, comments gratefully received.

Thanks.