How small a house could you live in?

I've thought about it for a bit and the Harbinger is something I could live in provided the upstairs was nice. Even so, it's just too narrow. I can live in a small place but if it's too narrow I feel claustrophobic. It's all on how you furnish it though. And how much money you have to furnish it. There are some kick ass things you can get that are super damn minimalistic but they cost way more than their 'normal' counterparts.