Mac OS X on Linux? (part II)

I e-mailed John Siracusa and asked him about the plausability of swapping OS X's low-level architecture for Linux (see post from yesterday). Here's the exchange:

On 12/30/03 10:43 AM, Jeff Solomon wrote:
Hey, John. How hard would it be for Apple to swap Mach and BSD out of
Darwin and replace those bits with the Linux kernel?

Very, very hard. Trying to port Mac OS X's IOKit driver architecture alone
(with binary compatibility unless Apple wants to start from page one again
on the driver support front) would be a nightmare.

I think a Linux-based Darwin (and OS X) could be a nifty trick for Apple, and
a killer app for Linux.

There are many disadvantages, almost no advantages, IMO.

So, that's John's take. Interesting.