Using libei to emulate a game controller

libei appears to work fine for generic remote desktop use cases, where the compositor gets libei events and translates them to Wayland events (wl_keyboard, wl_pointer). Would it be possible to use libei to emulate a gamepad input device too? This would be useful for Steam, where it wants to have a virtual gamepad device that games utilize rather than the normal input devices.

For context, this would be part of wayland/wayland-protocols!110. The Wayland protocol deals in giving an evdev file descriptor to clients, the idea would be to use libei to create a virtual device that can get returned as that file descriptor.

Is this the right place to deal with this? Would it be doable? I'm guessing it would be somewhat related to #38 (closed), where it was asked why libei doesn't create "real" input devices.