I went on an extensive search for yarn this weekend, and the only color I was happy with was not actually cascade 220 superwash, but in fact an acrylic blend. . . don't hate me - it's only the borders, and you don't have to knit with it!
I've completed the borders on the 8 squares I have, and can't wait to get started on more. Alas, wait I will, since I'll be out of town till Monday.
Here's a photo of the current state of the ABP. The color's a little off in the picture, but you get the idea, I think :)