Is it possible to allocate a joystick button command to toggle the sayit and sayit plus boxes ?

That is not currently in the plan.  I can add it to the potential future enhancements list.

Curious as to how you envision that would be used since you must use your mouse to select the SayIt Phrases.

Thanks,

Dave

P2A already has that feature! ...sort of. There are many readbacks that are listed auotmatically and you just need to push the Sayit button. I sometimes unbind  the PTT button in the yoke and bind it to the Sayit command. That way I can readback or send a Sayit command after selecting what to say with the mouse. Specially useful when flying late at night and not wanting to disturb the family.  My P2A is running in a remote PC.