shade-tolerant vines

Hi everybody. I'm looking for some recommendations for a vine with some pretty specific requirements for a permaculture design project I'm working on for school...
- Hardy to zone 4 or colder
- Shade-tolerant (on North side of house)
- Some sort of practical use that fits in with the permaculture ethos

I've looked at Boston Ivy and Virginia Creeper, which have the benefit of acting as insulation in the summer. However, are there any other vines that are more multi-functional? Edibility? Use as fodder for livestock? Insectary?

Thanks

head over to Plants for a Future's search page and enter your criteria.  a few that come to mind: arctic kiwi (Actinidia kolomikta), honeysuckle (Lonicera spp), Schisandra spp., maybe a grape (Vitis).

also, there's shade, and then there's shade.  I've seen akebias growing on the north side of buildings without any direct sun, but it was still fairly bright.

there's a plant grows out here called Oregon manroot (Marah oregonus).  weird plant.  the vines look fragile and die back every winter, but they grow real fast out of a giant tuber that can weigh over 200 lbs.  the stuff has a few medicinal uses, and the root can make a sort of soap.  smells like ripe fruit when it's broken open.  I've also heard that the shredded root added to water stupefies fish so they can be easily collected.  anyhow, not the most useful plant in the world, but it's sort of a fun oddity that's very common around here.

You might look at hops. Tough as nails once established and useful for other stuff as well as for making beer.  If you are into making beer, you can get various strains according to what sort of beer you prefer. It's also a vine that will shelter birds and other such wildlife. However, a trellis is required and it better be a big one; the things can grow 15 feet or more in a short summer (they die back to the roots in the winter and then start again each spring, at least in my area).

I've seen it growing in northern BC on the north side of a house but the site was pretty open so it still got lots of  light,  there wasn't shade from trees for example. I don't think it would be happy without any light at all to speak of. Also, it can be irritating to the skin to clean up so gloves are in order to do that. It will grow about 3000 times as fast as Boston ivy will and is tougher as well. Doesn't have the colour of the virginia creeper come fall though. 

The Japanese yam might work and you can eat that. You may need mulch to keep it warm enough. I use large crates full of soil for chaiyote squash, They can be stacked indoors for winter if you have a basement

To my knowledge Kiwi grows everywhere that Virginia Creeper does and produces fruit in most of the places. As such I think that VC is both overrated and overused.

hedera helix or ground ivy is a great deep shade tolerant vine in the aralia family.... brings in all kinds of beneficial insects... lots of other uses... here's pfaf's listing
http://www.pfaf.org/user/Plant.aspx?LatinName=Hedera%20helix

i might also suggest as an edible caucasian spinach.... hablitzia tamnoides.... it likes shade, is perennial, and produces food early in the season