Looks great! But the stinger is in the tail : "I think the next thing to add is indexes. Currently everything works
via a linear scan of the database."
It depends on what you use it for. Without indexes, it could be used for testing without setting up a local MongoDB server, as long as there aren't too many records.
Thanks. Re: indexes - patches welcome :). I don't expect them to be hard to build though. Since embedded-mongo is in memory, they're just a bunch of hash tables.