This is my construction for a RaspberryPi with a PiCam (running Octoprint). Both long arms fits at the back of the Makergear M2 frame.
Short and long arms are connected with the connection pins.
The RaspberryPi holder fits between the short arms.

RaspberryPi circuitboard fits in http://www.thingiverse.com/thing:48085.
Make a slot in the case for the PiCam flatcable and glue the PiCam holder http://www.thingiverse.com/thing:189420 on the case

31-12-2013: Updated RPH.stl for better powecable clips

05-07-2015:
Timelapse, to give you an idea how it looks like

http://1drv.ms/1KEaz4R

Printed on MakerGear M2:

• PLA 1.75mm, 195 C
• Heated bed 60 C

Repetier settings:
bottom_solid_layers = 3
bridge_acceleration = 75
bridge_flow_ratio = 0.75
bridge_speed = 60
perimeter_acceleration = 1500
perimeter_speed = 80
perimeters = 3
raft_layers = 0
small_perimeter_speed = 50
solid_infill_speed = 85
support_material = 1
support_material_angle = 0
support_material_enforce_layers = 0
support_material_extruder = 1
support_material_extrusion_width = 0
support_material_interface_layers = 0
support_material_interface_spacing = 4
support_material_pattern = rectilinear
support_material_spacing = 4
support_material_speed = 65
support_material_threshold = 0
top_infill_extrusion_width = 0
top_solid_infill_speed = 75%
top_solid_layers = 3
travel_speed = 300