It appears the answer is yes… habitable sheds are popping up in the UK.
“A fascinating business proposition in Oxford is moving the shedworking/tiny houses story forward.
As reported by the BBC Oxford businessman Robin Swailes is marketing £25,000 shedlike pods (3m x 2.5m) with electricity, kitchen, bed, toilet, shower, underfloor heating and running water as small homes for those struggling to get onto the property ladder in the city.”
via Shedworking: Could garden offices solve the UK housing problem?
A new design from Historic Shed.
Kevin from the 
Alt. Build Blog has an update on a Japanese Style Shed they reported on a while back.
A new prefab shed on the market that might make a good tiny house. This one is only 8×8 but other models are said to be coming soon. This one was spotted at a Lowes in Colorado.
Just to give you a peek inside the shed craze in the UK… the BBC recently covered the popularity of shedworking in a recent broadcast.
Here’s a great time lapse video that shows how a tiny stick-built building goes together. It nicely illustrated how little building material is needed and how few steps are really needed to provide a basic structure. I first saw this on