I've come across what I think is what I'm looking for.
It's called AuFS.
It merges multiple folders into one location. It also manages writing to all the locations.

However, I cannot seem to get it working. I obtained it from a suse repo, and installed it, but the syntax (and examples) found on the net and in the man pages, just doesn't seem to work form me.
When I try to #mount a location based on the given syntax I get the mount -h screen.

Can anyone help me?

Anyone out there use this before?