My application has 1000+ files which could total up to 300MB.  What I want
to achieve with cascading updates is:
   1.  User installs full application on their computer
   2.  After 30 days, there will be updates to a certain library of files
(Version 2)
   3.  After another 30 days, there will be more updates and additional
modules (Version 3)
   4.  After another 30 days (Version 'x')....

What I want to do, instead of having to copy all of the Version 2 files over
to Version 3 (on the server) for the full update to perform, I want to do
some type of cascading update where Version 2 files would download only if
required, then Version 3 files would download if required.  This would
prevent a user who already has Version 2 upgrading to Version 3 to
re-download Version 2 files again.

One other thing to note is that I have edited the Launcher to check for
version directories (ie. 2.0.0.0) and move the contents over to the original
installation directory before launching the application.  Doing this
prevents me from having to copy the complete application (300MB+) over to
the 2.0.0.0 directory when there is only 5 files totalling 1MB that have
been updated.  Although doing the reverse of what the Updater Application
Block documentation mentions means that I do not have a version history on
the client computer, it allows me to reduce the amount of HD space used in
the end and also makes it easier to continue with Automatic updates if the
user installs a previous update from CD (ie. User installs full
application - Version 1 - then installs update from CD - Version 2 - then
runs auto-updater - Version 3)

I have an idea of how to accomplish this, but I just want to see if anybody
else has done this first so that I don't have to "re-invent the wheel".

Thanks,
Jody