I was looking around for something else and came across this. Although it refers to crochet, you could certainly make and use these for color knitting as well. I have some of the plastic bobbins, but I think I'd like these better. I'm going to make a few and experiment.
I could have used this video about 2 weeks ago, before starting my horses pullover LOL. At least now I'll be good to go for my next project, rather than buying some (they are in my wish list at the moment for the next order!).