Inspired by the Raspi camera holder for the i3 Mega (https://www.thingiverse.com/thing:2275881) I designed a holder for my webcam, I use to monitor my prints with OctoPrint. This way the growing of the part in timelapse video is much smoother to view, as if the camera was at a fixed position.
The holder needs no screws and is just clamped to the sheet metal below the print plate.
A demonstration video of the 20 mm hollow calibration cube (https://www.thingiverse.com/thing:271736) can be found here: https://youtu.be/Uj4-BXuUzgA)
UPDATE 2017-08-18: After some weeks of used I encounterd a problem with this holder. The plastic deformed a bit and blocked the movement of the heatbed in the most frontal position. I planned a new holder which only clampse on the right side of the sheet metal. Maybe it is enough, if you increase the infill so that the holder does not soften. If I am satisfied with my new design I will upload it here.
UPDATE 2017-09-16: I uploaded a new design (filename: Kamerahalter V3.stl). It now clamps at the side of the sheet metal, so it cannot interfere with the rails, even if the material softens.