A Dockerfile that does the following:

• Bundles Datasette master
• Python 3.6 most recent version (or 3.7 if it has been released)
• SQLite 3.23.1 (or most recent release) such that "import sqite3" in Python gets that version. Ideally with the json1 module baked in by default, but having it loadable as an optional module is fine too
• SpatiaLite 4.4.0-RC0 (or most recent version) such that it can be loaded as an optional module
• Uses multi-stage builds to stay as small as possible

Note that the current "release" of SpatiaLite is 4.3.0 which is missing key features like https://www.gaia-gis.it/fossil/libspatialite/wiki?name=KNN - 4.4.0 probably needs to be compiled from source.

I don't know the best way to get a current SQLite version bundled for Python 3. Maybe https://github.com/coleifer/pysqlite3 ?