This was done as a fun, group build at the Chicago Hackerspace, Pumping Station One. The goal was to make a super simple very small delta. It was more for the fun of the build than anything practical.
We used a stationary extruder and a moving build area because it actually made more sense at this size. The build area is about 100mm diameter and about 50mm tall.
To satisfy the people who said it looked upside down, we actually tried it upside down...it worked. See the video here.
There is a bolg post with all the details here and the complete source files are available.
Click view full size on the images because Thingiverse is cropping them in the preview window. On most screen it might actually be full size :-)
Update: I added some recent features.
1: Magnetic base. This makes it easier to get parts of the base.
2: I lazy susan filament feeder.
3: Some lighting.
Read about the upgrades here.
I have access to many types of printers and this little guy is making the best prints of all of them.