Current design will have two center plates like most of multirotors have, it also have carrier boards to carry electronics like APM, APM shield and Receiver. Another carrier board will be mounted under main frame to be as a battery holder it also creates supporting base for future landing gear addon.
It's been planned to have a power distribution board above center plates.
Square center plate having X setup, it also holds + setup on this board
Center plate with carrier board. Carrier and also power board (not shown) can be rotated with 45° steps on all designs. Power board will have 10 mm spacers and carrier 20 mm.
Square frame with carrier (rotated +45°) and power board.
And last but not least round Quad/Hexa center board. Quad power distribution included. Both carrier and power boards can be mounted either above or below center plates. They also fit on both square Quad plates and round Quad/Hexa plates.
We are closing finishing line so not any major changes should happen. Tho this is still preview on what we have been working behind the scenes.
First frames are being build as we speak..
I will post more pictures on development wiki https://code.google.com/p/arducopter/ during new couple of days.