As mentioned earlier, one of the features of FC3 will be a new 6 DOF cockpit for the Su-27 Flanker. This is in addition to new cockpits for the F-15C, A-10A, and Su-25.
Here are some first look, work in progress images of the new Flanker cockpit.
Two point though:
1- It will not be ready for the 1.2.3 update.
2- As part of the Lock On: Flaming Cliffs series, it will not have mouse interactive cockpit.