I suppose a real great business venture would be recycling plastics. I would also prompt all TOD readers to demand rules for the mandatory recycling of ALL plastic products and banning the use of plastic bags at grocers, retailers and all other businesses as they are no longer a need.
Reducing plastic use is certainly a good thing...as long as it doesn't vastly increase use of other fossil fuel dependant products.  For example, it turns out that in the paper versus plastic grocery bag debate, plastic wins.  But that's a silly debate because cloth bags or plastic bins are so much better than both.

But plastic use (as it pertains to peak oil) is such a small contributer compared to transportation fuel use.  It seems a waste of mental energy to worry about paper versus plastic at the grocery store, and then put everything in the trunk of your car and drive back to your natural gas heated and electrified home.

Of course, every little bit helps.

Plastic bags are made from NG, thus my comment. Certainly, the expandable cotton mesh bags that are quite strong and hold far more than thought are best; they are what I use.
I've been using the same woven-plastic bulk bags for almost twenty years! They're kind of cruddy looking, but my gosh what a fabulous use for plastic. I've saved hundreds if not thousands of paper bags and plastic bags by simply remembering to bring the old clunky woven-plastic bags to the store with me.