Ideally, your basic neccessities piled into a statue of a mob made of an outer layer of obsidian and an inner layer of wood. What each contains basically depends on how much room the mob allows inside it. And some, like the Ghast, only have one function.
Of course, you have to fill it up yourself. 

Each of these suggest you put them on flat land, Sans the Ghast version, which floats. They also assume you don't have any mods, so feel free to re-purpose them to your needs. Yes, i'll allow you to punch holes in it, but nothing too drastic, please. If you need Obsidian, go get it yourself. =P

Also, you can go ahead and color it with wool on top of the obsidian layer if you wish.