Greg Kelly (from google+) has been working on quite a neat and simple mini FPV quadcopter. The design is based on two rectangular carbon fiber plates with some 3D printed parts to mount the arms and motors. The overall weight of the frame including battery/motors is about 259g. I think one of the best ideas was to use some cable ties to mount some of the stuff instead of screws as its much lighter.
In order to choose the best motors Greg built a motor efficiency testing jig as described in the video below. From the looks of it its also 3D printed 
Final Parts List
- Turnigy Aerodrive SK3 - 2118-3100kv Brushless Outrunner Motor
- 5030 Propellers (Red) - 3xCW and 3xCCW
- Turnigy nano-tech 1200mah 2S 15~25C Lipo AIRSOFT Pack
- Carbon Fiber Tube (hollow) 8x750mm
- Woven Carbon Fiber Sheet 300x100 (1.0MM Thick)
- TURNIGY Plush 6A /.8bec/6g Speed Controller
- Quadcopter Flight Controller
- FPV gear