That's a gorgeous scarf! I bet it could be made with other like weight yarns. I'm thinking that a yarn with an interesting colorway could probably be substituted and then you wouldn't have to change yarns throughout. Just do the mitered squares. Noro yarns come to mind as I've done mitered squares with them and they turn out absolutely gorgeous!
"The world now has the means to end extreme poverty, we pray we will have the will"
knitncook there, too!
OTN: Laughing Carrots; Jaywaler
FO: Potamus socks; Palindrome