Saw an link to Xtracycle, a company that is hoping to make bicycle travel more common by providing better carrying options than standard saddlebags/trailers. It even adds a “backseat” so you can more easily carry a passenger. As they say, a picture is worth a thousand words:
You can also add on an aftermarket power system called Stokemonkey. Thanks, Josh, for pointing that out.
Also, for those of you who want to bring your own grocery bags to cut out waste, go to this site.