I'm from old school on engine idleing,
so before I made comment, did a bit of fishing around and updated my knowledge.
Here's 3 links, I read amongst a whole lot more.
Vehicle Warm-Up | Office of Energy Efficiency
http://www.epa.gov/region1/eco/diese...uck_Idling.pdf
http://www.ytcleanenergy.org/docs/idlefree.pdf
I am still a bit sceptical as all the information seems to be one sided, driven by the green movement, and opposing voices in these political environments tend to be just a dull whisper.
In all cases when you take off, start slowly and don't push the vehicle too hard for the first few km/miles to let the drive train (gearbox, diff, wheel bearings) warm up as well as the engine, the colder it is the longer you should take it easy.
As for starting cold:
In normal mild weather, you can pretty much start moving as soon as you start the engine.
In cold weather, give it up to 30 sec to get oil moving properly.
In very cold weather (freezing or below) give it a few minutes to lube up a bit, if you use a block heater, obviously you can avoiid this time.
One thing I noted in a few places regarding hot idle and shut down, for cars generally, 30sec is the breakeven time for fuel saved vs fuel & maintenance cost to start up again.
So I will adjust my own behaviour appropriately and keep seeking relevant information.