I'm also working on an arduino sdk for the esp8266.
I have installed the c++ compiler in a private cloud running on debian and I'm currently writing the api.
I've already written HardwareSerial.cpp and I almost implemented Wiring. I also began a c++ api to access the wifi.
I hope to release something next week.
I'm also working on a breakout board for the Wi07-3, so I will be able to access all the gpio with Arduino code.
I believe the easiest way to integrate the compiler into the arduino ide, is to have a plugin sending the source to a cloud and get back the binaries.
When I'm done, I will write a tutorial to explain how to setup a compilation server.
Regards