I’ve got some ideas for you.
If you can get to a Decathlon store (they are widespread in Europe, esp France) they do the Bionnassay climbing trouser which is really good for ski touring
http://fr.decathlon.com/pantalon-bionnassay_113_32350.htm?xtor=ADI-31&T1=Affiliation&T2=Criteo
It is a lightweight, waterproof shell with side vents for when it is hot. Cost is just 45 euros. Lots of the Grenoble ski touring crowd use them. It has an internal gaitor to keep snow out of your shoes. I would suggest cutting the heel loop as they are really uncomfortable. Also braces to keep them up when you are skiing. They give really good movement and dry quickly. I would wear underleggings (or your wife’s 100 dernier tights) if it is cold.
If you want to be a bit ###, and are looking for a ski mountaineering trouser try the Salopette Capcir 700
http://fr.decathlon.com/salopette-capcir-700_115_32202.htm
this is really suitable for fast day ascents - remember to pull the trouser over your inner boot or you will get very wet feet from snow. It has a double zip for people who like to relieve themselves on the ski trail (or on the move 
.
Sport Conrad have a couple of offers for ski pants too:-
http://www.sport-conrad.com/index.asp?disp=kategorie&kat_id=26
