Just read those today (you beat me to the thread ), interesting stuff.
From Scott Burgess' article above (on the XTS):
"Cadillac says the new model will offer powerful direct injection V-6 and firmer suspension and play a role as Cadillac's flagship inside and out. No official word on whether it will be front wheel drive or rear wheel drive, though it will likely be all-wheel drive. If Cadillac wants to remain true to its performance mantra, the rear wheels need the power first."