Never. My next house is going to be bigger. We have 2100 sq.ft, and it's just not laid out well and not enough space. With modern building technology allowing tighter building envelops, you can have your cake and eat it, too (to an extent). Give me a nice timber frame hybrid any day:
I've been looking at videos on youtube since this thread started (and sort of ended) I kind of like the idea of doing a small (ish) home that's totally off the grid. I think it would be pretty sweet, not really a "micro-house" but something small like around 600-800 sq/ft with an upstairs loft and a crawl space. Rig up a nice sized hybrid wind/solar power system, a composting toilet system and a tankless water heater (probably LP). Wood heated (could also heat water). It would save me a freaking fortune in power consumption.
We have about 1,000 square feet with two bedrooms. We can't have any more children so that's enough. Living in the country might be nice, but here the girls can walk to school and there is a troop of kids in the neighborhood for them to play with. A bigger house would just be a lot of unneeded space to maintain.
I wouldn't ever go all out small house, but if I had the savings currently, I would build a small living area in a shed on our farm. Kitchen, living room, bathroom, a loft, and then the garage for all my crap. That would suite my living needs just fine for now.
It might be neat to start a kickstarter campaign and build an experimental eco-friendly house. I have a few ideas that would be pretty cool and cheap to implement on an "off-grid" house. Maybe document the build and the techniques to give as the offerings. I'd like to experiment with a mycarta skin and flexible solar panels for their efficiency and weight. It's absolutely ridiculous how much the cost of building a house and utilities has become. The power companies are crooked as a barrel of snakes. I priced having electric run over on one farm for a new house and they shot me a price of 50k...that would be laughable...if rape was funny. Said I wouldn't have to pay it all at once, they'd just add $50/month on to the bill... On top of the cost of the power, that would be pretty pricey. I'd think you could build a pretty impressive power system for that kind of annual investment and not have power outages and spikes three times per week like I have now on their antiquated crap system.
A doctor my wife works with was on that show. She said the whole show was totally staged. They had Actually bought the house a year Pryor to the taping of the show.