Vast vacuum tube networks certainly never took off, and it's not like robots are flying around and delivering our packages for us. Maybe that's because both ideas rely on extensive changes to come about — maybe we need something a little more grounded. Or should I say a little more undergrounded?
Designer Phillip Hermes' "Urban Mole" would crawl through a city's already existing subterranean network of pipes and sewers. Ideally, electric rails would power the units as well as guide them along toward their pickup and drop-off points, where folks like you and me can receive our packages.
Hermes envisions his moles as being the size of a shoebox and being able to make cross-town deliveries in as little as ten minutes (depending on how big your town is, I suppose). A shoebox, huh? Sounds pretty small, but maybe by the time we have these buggers crawling underground our society will be relying on component construction.
Here's another click-to-enlarge shot of the Urban Mole: