Volupta, have you seen the book Knitted Tams by Mary Rowe? She has lots of color ideas and patterns to mix and match together. I just finished one in Tahki Donegal tweed for my husband, in various blues and grey.

an old weblog entry of mine, with links to other people's tams based on Rowe designs.

almost all of my stash is from the goodwill or other thrift stores!

That's because I was turned onto knitting by kaffe fasset's books. He uses a zillion different colors blending together, so small amounts work great!

some of his designs use intarsia. others have you  make a ball, using a few yards of one color then tying on a different shade.