This is an remix of my other quick release Arduino holder:
http://www.thingiverse.com/thing:2165053
This time I integrated an flans to mount it against alu-profile frames. I personally don't use such profiles. But they seemed to be loved.
The Arduino pcb just snaps in and can be released by pushing the hook. There are also tree screw holes with embedded nuts to screw the board down, but this is not quite needed. Even the complete RAMPS assembly is held proper.
The mount is intended RAMPS boards on an 3d printer, but will serve any applications of an Arduino Mega 2560.