Trying this now... On Nokia N900, a script containing:
gst-launch v4l2camsrc device=/dev/video0 ! dsph264enc ! rtph264pay ! udpsink host=LaptopTargetIP port=5434
or
gst-launch v4l2camsrc device=/dev/video0 ! ffmpegcolorspace ! jpegenc ! multipartmux ! udpsink host=LaptopTargetIP port=5434

On laptop, installing v4l2loopback with module-assistant, to perform
sudo modprobe v4l2loopback
And then something like
gst-launch udpsrc ! decodebin ! v4l2sink device=/dev/video0
or
gst-launch udpsrc ! multipartdemux ! jpegdec ! decodebin ! v4l2sink device=/dev/video0

So far, problem is, libv4l2: error getting pixformat: Invalid argument

And dummy camera on laptop is black.

Thank you. Best wishes.
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Per aspera ad astra...