I think there is no need of isolation. Why will a blind person like me who knows to use linux use a special distribution of linux? and for those who are just learning, well there is no point in isolation because then the starters will not get the real hang of linux. never in their life will they be able to do some complex tasks like administration etc. And by the way when we talk of integration of blind people in the sited world is this not a wrong signal to the blind community? when you want to provide the blind what sited gets then there is no scope of isolation.