"Without database access, sockets, threads, POSIX, or a portable FFI (which I could at least use to write many of those features), my programs can't talk to the outside world, and that makes them basically useless."
I'm embedding it so it's going to talk to my C wrapper for everything. How are you using it?
Also see: Using Python libraries from Lisp http://common-lisp.net/project/python-on-lisp/