Kenji Arai
Please see my note book http://mbed.org/users/kenjiArai/notebook/freertos-on-mbed-board-with-mbed-cloud-ide--never-/
This is too old.
Below is another FreeRTOS on mbed.
http://developer.mbed.org/users/rgrover1/code/FreeRTOS/
I don't know it works well or not.
I have not evaluated it.