My local department store carries some Desigual brand clothing. I'm quite inspired by the way they mix fabrics together, espeically in their knit tops and dresses.
They are quite careful about their brand and I can't find anywhere where you can save their pictures, but you can see the styles here on the Desigual Website.
One of the KnipMode magazines I have tries something similar to their styles, and in the spirit of using leftovers of knit fabrics I have been thinking about this for a while.
Basically you need a number of different fabrics - at least 3 - which have a common base colour. They are often dark or a strong colour but don't tend to have light backgrounds. I fancy one using black based items, though I think it would actually be quite tough to find enough suitable fabrics from my already existing scrap box. I think also that Desigual have some large graphic prints which are not found elsewhere. I must say I love the idea of all different fabrics used for front, back, each sleeve and the neckband. A lot of their tees have one sleev in a different print than to the other. I think it has to be done very deliberately though or else it ends up looking a little crazy.