I found this studio at Urban Gardens.  What a cool ideal.  I love the efficient use of space.  Don't know if I would have enough space to build this, (due to my small yard and other future plans) but if I do I would probably partial enclose it with plexi-glass windows with a frosted treatment.  So I could choose to have the windows closed or open (we get lots of mosquitoes here in MN).  I like the railing around the top.  I would feel scared that people would fall otherwise.  I would probably make them even higher just in case.  I would also use cedar for the wood and paint it with an outdoor paint to make sure it would last for a long time.  I would also put pavers down for the floor and add an outdoor rug.  A girl can dream huh?