Unless you are knitting in the round and making the scarf a tube you will have a very one sided scarf. The back side of fair isle is strands of yarn because the colors are carried across the work. For that reason you don't see as many fair isle scarves. Are you planning to make a tube?
I did find these, but I'm not sure how they are knit.
Scarf Style has one called Fair Isle Jazz
Knitty 2007 has one called Fair Isle Rapids