I got post from Aliexpress today. The WIFI Witty / Gizwits ESP-12F module arrived.
The ESP8266 module family grows and grows and prices come down. You can order such a module for 3 $ and less.
You get an ESP-12F module and a LDR, a RGB-LED and a switch on this board. Additionally there is a stackable programming board w/ a CH-341 USB chip. I flashed NodeMCU Firmware and now Lua is running on it. Two simple test programs (witty.lua & witty_pwm.lua) for this module showing the pin configuration for the existing peripherals (LDR, RGB-LED, Switch) are available on Sourceforge.