>Yes, as Wes pointed out, TopGraph'X has written X-windows 100% in Ada, and
>a group are working on writing an OS in Ada.

Although it is true about AdaOS, I was on their mailing list for about 6 months
and all they did was discuss licensing! I got the impression there was nothing
concrete to show for the efforts, so I unjoined the list. I am sure though that
e.g. Wes would know more about this at the moment.