After what was basically a flurry of typing, the snegg Python bindings for libei are now available. This is a Python package that provides bindings to the libei/libeis/liboeffis C libraries with a little bit of API improvement to make it not completely terrible. The main goal of these bindings (at least for now) is to provide some quick and easy way to experiment with what could possibly be done using libei - both server-side and client-side.  The examples directory has a minimal EI client (with portal support via liboeffis) and a minimal EIS implementation. The bindings are still quite rough and the API is nowhere near stable.
A proper way to support EI in Python would be to implement the protocol directly - there's no need for the C API quirkiness this way and you can make full use of things like async and whatnot. If you're interested in that, get in touch! Meanwhile, writing something roughly resemling xdotool is probably only a few hundred lines of python code. 
 writing these also exposed a few bugs in libei itself so I'm happy 1.0 wasn't out just yet
 at least the input emulation parts of xdotool