after uploading my initial design, I got several feedbacks. So I tried some configurations, and finally came up with this Rev3 design. The major difference is that the video TX antenna is between camera and battery, so battery size can be incrased up to 1300mA 4S which is used in many 180 configs. The only limitation is 33mm width / 76mm length. Other electrical parts are the same. Another difference is that motor angle is 10 degrees instead of 15.
Updated STL files are uploaded to GrabCAD.
*** UPDATE ***
I also finished the design of a flat motor position version, that means motors are flat and camera angle increased to 25 degrees. Files can be found on GrabCAD.
Also, there was a question related to ESC ventillation. If neccessary, holes can be drilled over the ESCs through the arm (since the wall thickness is about 2 mm there), but it is better to avoid them during print for best result.
*** END ***
First prototype, after acetone vapour (I hope I'll receive electrical components within 1-2 weeks too):
I also added some 10x4x1 mm neodymium magnets as a canopy lock if battery and velcro not present: