I was dying to answer this thread!

I have the Warn X8000i Winch and combo mount and searched in vain to find a way to get it on.
ARB and Calmini are the only ones with bumpers that can mount winches.
I called Warn and they don't even have anything in the works for the Xterra.

BTW: I have a Warn X8000i Winch and Combo mount for sale if andbody wants to buy it.