I have just finished the design and prototype phase of my open source quad frame. Its a 1.5mm G10 frame for 10"-12" props. I am in the process of designing a two axis gimbal for it, but to do this i need access to a faster prototyping process. I have entered the instructables shopbot contest and I really hope that i can win that as it will make prototyping so much easier. I've spent approximately 3 months on this design so id really appreciate it if when downloading the dxf you can vote for my instructable.  

The DXF is on the third page http://www.instructables.com/id/Quadcopter-frame-design-fiberglass/

Features 

The design is made up of a very secure "ball" that protects the electronics and attaches the arms, making it extremely crash proof.

The arms are reversible so you can fly with some up and some down at the same time as the thrust line stays the same.

ESC's have their own mounting boards.

Motors lie inboard of the arms for protection.

Large battery bay with strap holes.

Large electronics platform.

The Design is fully modular for easy replacement of parts.

No glue is used only bolts for easy assembly and changing of parts.

Extremely strong and high GPS board. 

A gopro camera can mount directly to the top or bottom.

Sonar mount on landing gear.

Have fun with it 

Chris