Check out this tutorial on making a multi-strand necklace as posted by Love Maegen.
It seems like a fun idea to troll through flea markets and yard sales looking for color combinations or specific styles for this necklace.
I have also found that when looking for strands of colored pearls or big glass beads, or whatever really, eBay can be a good place to look. You can often find deals, especially on the cultured and dyed pearls, that are much less than at traditional bead stores.
The possibilities are truly endless with this project