Hello Niall.

You can find some interesting information on-line.  The term itself is French, so you may want to research its origins in France.  It has been used for interior designs and architectual accents over the years.  Later, it became more popular as an art form.  You're seeing modern uses right on this site.  Look through the articles at this site for further information.  Please check out the galleries for some prime examples of how this medium is being used today.

The process of paper being mashed and then stuck together has been around before it was called Papier Mache.  Earlier examples of this process involved plant fibers and resin, etc.  Was it ornamental or practical?  There is not much historic documentation available on the topic.  However, museum archives may be a good starting point.

As far as batch production, that's up to you.  You could press it into molds or come up with a method that is suitable for you.  If you want to explore industrial possibilities, then you may want to research trade journals that offer equipment for similar purposes.

The information is out there.  There are organizations and companies that specialize in paper and paper related products.  This includes, but is not limited to recycling.  Perhaps a little experimentation would help you find the best method to create a product.

Good luck.

Rozani