I probably wouldn't get around to writing anything until after the holidays, either. I could probably write up a general shipping guidelines the way I do it, and maybe you could summarize your experiment.
I think there was an old thread on Fauna at one time detailing some info somebody found out about airplane temps, I think on FedEx. If anyone has time (or inclination) to find it, maybe post a link here.
When packages are held at a regular, FedEx staffed FedEx, so far all of my customers have said that they were held in the heated office. So I don't think they are held TOO long in the cold (or hot in summer) warehouse. I really think that holding at FedEx is a key to successful, low stress (for animals) shipping in cold or hot weather.
Another "trick" I have used in really cold or hot weather is to put the deli cup inside of a bubble wrap type envelope mailer. I stuff it with crumpled newspaper to make it as filled out as possible, to contain as much air as possible. Then I seal it to provide more insulation than just the box. I have considered putting in a gel pack (usually used for cooling, but at room temp) to provide thermal mass so the package won't change temps as quickly. A soda bottle full of water would do the same thing, as long as the box is big enough, and as long as you are sure the bottle won't leak. I haven't actually done this myself, but may do so in the future. (the next person who wants to experiment as Wade has, could try using some thermal mass to see how much difference it would make).