no way... it'll definitely cost more than that. the M5 currently costs $85k. with a couple clicks of the mouse, you can easily configure that thing over $100k (better sound system, nicer seats, etc.). given that the X5 & X6M are both testbeds for the next-gen M5/M6 engines, i doubt BMW will let them go for anything less than $95k, plus options and taxes (gas guzzler). figure it this way: this is a premium, premium SUV.
the way i see it is this (conservative #'s):
X5M MSRP = $95k
X6M MSRP = $99k