Hey Trisk,
You know, I do dress for x country skiing like I do for cycling. I don't ride when it gets below 40 (or 30 for very slow hybrid rides), but I just heat up so much when I ski. I wish I could tell you the style of my pants. My DH ordered them for me a few years ago, when we got back into skiing. They are like tights, in that they are "tight," and have ankle zips. The backs of the thighs are wool and the rest of the tights are a pretty good windproof type of material. These were my first piece of Ibex, although I had no idea where it would lead me!
What I usually wear for skiing: base layer, like a Craft LS top, or silk long underwear top. Once in awhile I wear a Smart Wool base layer, but it has to be pretty cold (like in the single digits). I find the Craft base layers keep me soooo warm. My mid layer is either a mid-weight wool piece or a mid-weight fleece piece. Most of them are cycling tops, although I have a couple non-cycling fleeces, along with my Shak hoodies I have worn. My jacket is a Go-Light. It's pretty thin and windproof. It is not a soft shell and not waterproof, but it's pretty water resistant. I have also worn it for winter riding. On the bottom I wear Ibex boy shorts and the above pants, or a pair of wool Jones Ware hiking pants. They are pull ups and have flared legs. If it's below 30, I wear a pair of thin silk long underwear, too. If it's super cold, like below 18 or so, I have another pair of long underwear that are mid weight, but are synthetic something. I wear wool ski socks, sometimes with a silk or polypro sock liner. That's it.
I add headwear according to the temperature, and often take my headband to switch to, because I sweat like crazy. I have a pair of Cabela mittens that are super warm. It has to be in the twenties to wear them. Otherwise, I wear my Pearl Izumi Am-Fibs. Yesterday I had my glove liners on, too. They have a nice little pocket for chemical handwarmers! I use those and foot warmers, when it's really cold. I had them on yesterday, because it was very windy, although not that cold. I start with a fleece neck gaiter on, so I don't inhale the cold air, but it drives me nuts after 20 minutes or so and I usually take it off, unless it's frigid.
I find the key to being comfortable is to dress in very thin layers, and for me, it has to be thin enough so that if I stop skiing for a few minutes, I feel cool. I just heat up so much, and then that makes me tired, uncomfortable, which makes me lose my form. I see a lot of people wearing way too much.