that's the biggest problem with these bikes. you can't even cruise down the street carrying a soda.
i've got the ammo can on my 24" bike, which will hold my U-lock and and a few other things, but if i need to go to the store i always have to bring a backpack.
i'd like to build up a "cycletruck" for going shopping and stuff. just need to find a cheap one.
something like this: