How to Build a Cheap Storage Shed (Playhouse?) (sewing room) etc or chicken coop :) maybe a dog house
Add insulation, acoustical caulk and an extra layer of drywall
La Mirada Tiny House - A tiny house on wheels with a total of 270 square feet (including loft) of living space in La Mirada, California.
House Tour: Inside This 150 Square Foot House By Molecule Tiny Homes - This house is only wide by long by high. Inside, it has two sleeping lofts, a full kitchen including a three-burner range and oven and a full bathroom with shower and tub.
How to Build a Small 12 x 20 Cabin on a Budget, via Instructables Tiny Homes