"we've been through this on the desktop and it seems that unixes are winning"

As much as I would love thet to be true, I cannot agree. The Windows crap still seems to have a long future.

And unless you are talking GNUStep, you more or less can't compile a Mac app on a Linux box and expect it to work. A POSIX app, sure, but that's not a Mac application - it only goes as far as not being Mac-proof.