In reply to Siward:
I'd definately utilise dehydrated food if going lightweight is a priority otherwise your bag will weigh a ton. You can save on fuel by soaking some of the food in a container first, early on in the day (hot or cold water) this reduces your cooking time and fuel consumption when you come to reheating it.
In addition, bring the food to the boil then use a 'Pot Cosy System', wrap the pot in a Thermawrap (silver jiffy bubble wrap) and leaving for 15 mins saves on the fuel needed and effectively simmers the food to fully cooked. You can get the Thermawrap from the Insulation section of B&Q or buy it more expensively from backpacking light.co.uk, tape it together into a pouch to cover your pot using gaffer tape:
http://www.backpackinglight.co.uk/product212.asp?PageID=110
You are going to need at least 2-3 litres of water a day so you will need to melt snow anyway, unless your dropping down to lower areas where the water isnt frozen. The amount of water you need to rehydrate a dehydrated meal isnt that much, maybe 300ml on average per main meal.
Cous cous is a great option as is chorizo and salami etc
I bought a dehydrator for around £40, you can make your own jerky/biltong (way better than the shops) and dehydrate food like tinned tuna (goes really light), stewed meats, fruit, baked beans, cooked pasta, sauces etc.
The key is not to dehydrate fatty or oily foods, so precook meats by boiling or poaching as opposed to frying.
This is a good blog site for general lightweight advice and recipies for dehydrated food:
http://www.andyhowell.info/Dehydration/
Have Fun!