Craig,
thanks for the detailed replies to Jerome's questions. Though I had actually understood correctly your design, this helped confirm it.
Today I was reading this paper about Envy's ancestor -
http://www.davethomas.net/papers/orwell.pdf
It was interesting to compare what this had in common with what you are doing and also what it lacked that you included.
Very off topic - about Bill's famous quote, I do remember reading it back then (I would say in Byte, but it would be unlikely that then people searching for it wouldn't find it there) and in the context (defending IBM's, not his, decision to "waste" nearly 1/3 of the precious address space on I/O) fully agreed with it. In the article you cited I saw the first mention of Ken Olsen explaining his own quote but that is exactly what I had always thought he meant (and I also agree with that).
-- Jecel