I won't upload any further AppImages, but I am happy to support the KiCad team to do it.
In the meantime, you can generate your own AppImages on a Debian/Ubuntu system using the
pkg2appimage tool that converts the debs from the PPA to an AppImage. To do this, run on a Debian/Ubuntu system:
bash pkg2appimage KiCad
This should produce an AppImage. If you are running into issues, please let us know at https://raw.githubusercontent.com/AppImage/issues.
You can also use
bash pkg2appimage KiCad-nightly instead. The AppImage for KiCad-201712301944+e062780 is almost 600 MB in size though - I am not sure whether this is correct. How big is the nightly build for macOS and Windows?
Note that if the KiCad team decides to provide official AppImages, these would likely be produced directly as part of the build pipeline rather than by converting from debs in PPAs.