See my response below. As to the mobile nature vs. fixed dwelling unit, I'm not up to speed on Springfield and Eugene code issues. Tiny Houses are not exclusive to one kind or other, and I'd hope that code would more broadly allow for "built in place" tiny dwellings in time, if not now. My main criticism is that current code and taxation is not encouraging these yet. The taxes are a huge inhibition to building tiny dwellings. The ratio of taxes and fees to square foot costs, skyrocket as the units get smaller.