I do plan on doing the dual channel Sonoff and the Sonoff POW. I have not considered adding the 4-channel version yet.
@tangcmin The headers for the Sonoff Touch are clearly marked inside. The only exception is GPIO0 which is needed to get it into flash mode. If you ground GPIO0 as shown in the below picture and then power the board via the FTDI adapters 3.3v, you will be able to flash the touch.