Yup. Considered it. I initially settled on no because it might compromise the design goal of 1:1 MongoDB/PyMongo compatibility. Now the idea is being revived as

Yup. Considered it. I initially settled on no because it might compromise the design goal of 1:1 MongoDB/PyMongo compatibility. Now the idea is being revived as an option alongside the two existing backends. I am concerned there might be an issue with some square-peg high level MongoDB operations simply not fitting into the SQLite round-hole but it's certainly something that's being investigated.