There's been loads of great ideas on how we can design for zero waste, but it's my view that companies will often always strive for the most convenient thing for the consumer, and this often results in lots of pieces of separate packaging.
The idea here is to create a charitable organisation, filled with the sort of brilliant people that come up with the ideas on here! Add in some experienced manufacturing process engineers, who understand the difficulties of production on a large scale. This new organisation could then create not only the designs, but a fully planned method of delivering these commercially. Designs and methods created could be patented and then licenced for free to anyone, in a creative commons fashion.
The organisation's aim would be to get manufacturers to use their designs - it could offer free consultancy to new and existing companies, so that any time a new product is created they can provide guidance on how they can use plastic sustainably.
Of course WRAP organisation already exists and does some brilliant work in this field, and so it could be subset of this organisation. However, I believe a separate entity would work better in this case, with people that can be dropped into other peoples business armed with direct expertise on packaging production.