How creative do you expect you'll have to get in a space that size?
Will probably end up something like the wee house layout wise, though not as modern in design: http://www.weehouse.com/wee/
The building is pretty cool as it was originally an ice cream parlor in the 1950's. It was going to be demolished, but a group saved it and moved it to the current location and now I'm taking it over.
I actually got the building for free since I bought the commercial building in front of it (well, negotiated it into the deal so I call it free). The commercial building was built in the 1860's and also saved by the same group. It is pretty unbelievable - has an arched doorway in the back where the horse/wagon pulled in with supplies for the general store and tavern that were in the ground floor. I'm going to finish out an apartment upstairs and have two commercial spaces downstairs - one for my business and one to lease out.
Admittedly, though, I must have limits for small living spaces. My favorite part of this exercise was opening the door back out into the rest of the apartment, upon which my studio suddenly felt palatial.
Just spent the last month in the middle of San Diego and now it is out to the desert.