When you create a superflat world, there is a customize button underneath the world type selection button. Select it, and then click presets. You'll see a box up at the top that reads something like:
Simply change the text to:
Now start your game (or make it hardcore for an added challenge) and you'll be in the middle of an infinite superflat village. Blacksmith chests are everywhere and waiting to be pillaged, have some fun!
You can mess around with presets more in order to change the biome, height of the ground, and other cool things. I'll leave that to you, however.