I was just noticing the other day that the D4, D800/E, and D610 (anyways ) have not yet dropped a nickel here in Canada after 18 months, at least at the dealer I use to monitor this sort of thing. To some extent I take this to mean that rate of production of the Sendai plant in Japan (D4/D800) is somewhat closely matching demand.
Nikon seems to design their strategy on maintaining, as much as possible, body prices, especially in the FX side of the lineup. Although I see in the UK retail prices do drop dramatically over time and in the USA you seem to get the "buy together and save" options.
Off topic, BUT I would LOVE to see what fps a D800S with EXPEED4 could do! D4S, D800S, D620 all with EXPEED4 would be what I would do as Nikon CEO, and I'd do it for competitive reasons to stay ahead of Canon and that upstart Sony The above would certainly be a cost to Nikon, but they need to be nimble in today's hyper-competitive market. At least until Nikon's mirrorless lineup grows beyond the Nikon 1 line (which it surely will do).