Devilites in a boss? I don't want to fight the same, long ranged monster 70 times in a row, and other monsters just wouldn't fit. They'd need some alternate monster types. This would be an interesting modification to devilite levels, but I'm not sure that it is possible to construct 5 sequential levels around devilites.
Just my thoughts on the matter. I think the greaver boss idea would be more easily integrated (t3 boss: greavstricken).
But this boss idea, this boss idea:
IS AWESOME!!! I remember this...........