We already asked this question with "1.6GHz" in place of "1.86GHz," but seriously Sony, is there some sort of weird embargo on high-speed chips to America that we aren't aware of? While we Yanks have exactly one CPU option for the newly released VAIO P (that'd be the 1.3GHz Atom), those in Japan can order up the VGN-P90S with a 1.86GHz Atom Z540 processor. Of course, it's a ¥15,800 ($174) option over the baseline Z520, but an option nonetheless.
Read - Sony's VGN-P90S page
Read - Order page