Tommie Wilhelmsen's Kolonihagen Summerhouse
Standard Disclaimer: We know, second homes are evil. But they are such wonderful demonstrations of the talent of young architects, and they so often demonstrate how much can be done with small spaces. They just as easily could be first homes, and some of them are gems.
As an example, Tommie Wilhelmsen's Kolonihagen Summerhouse is full of neat ideas. The big gesture is the sleeping loft hanging out over the entrance, creating a covered porch below and a lovely sleeping area above.
The furniture is all built in;
and the kitchen doesn't get any more minimalist than this.
See also the summer house Tommie built in association with Todd Saunders in ::Treehugger here