Its fast idle isn't as obvious as some of the vehicles I've driven before, so it's not something I've had to pay as much attention to (i.e. a giant clunk going into drive or something like that). I don't think it's really any longer than what you've experienced, but when it's terribly cold, I'll let it warm up in my absence. I'm not sure of even the exact RPM. I'll have to take a look, but have heard the difference, even just pulling out of the garage, with it idled up for, as you indicate, maybe half a minute, then coming down basically as I lock everything up and get myself in order.
I never experienced it until this winter, but if I drive away in those -30 C or colder ambients without much warm up and just hit the freeway, it won't go to top gear until temperatures come up, even if I try sport mode. I had heard about that from people here before, but never experienced it. I tried a couple really short warmups this winter with our extended cold stretch, just for the heck of it. Of course, I can't say I much care for that staying in "4" bit, given that in my experience, a transmission that isn't shifting means it isn't long for the world.
OilUzer: My worst cold weather noise experience was close to -40 when I started moving my LTD and the ball joint was groaning, then gave way. Now, if you want fun, try getting a tow truck in -40.