I-cord trim it or not, make it short or long like the model here and, of course, you can use any yarn you like. Elizabeth gives you both the encouragement and the information you need in the chapter on the Moebius from her book, Knitting Around. While knitting this one, a couple of ideas for variations popped into my head. It's a sure thing that I'll be casting on another right away. That's the beauty of EZ's work, it takes you beyond yourself every time.
And if you are ready to jump in, I hear we have just one seat left in the Moebius Vest workshop at Knit Knack this Sunday, February 24. We'll be exploring the techniques involved in the construction of the vest by making a miniature version and then we'll be getting each knitter's own Moebius going on the needles. Gerri has loads of gorgeous colors in the yarn I used for this model, Cascade Eco Wool, and she's still got a few copies of Knitting Around, though many have been going home from her shop with excited knitters. After getting to try on this ingenious design, they were sold. I am truly excited to be enabling the introduction of more knitters to this great volume of knitting wisdom. Will they be surprised when they see all the other goodies inside!
My own personal copy I've had since the day it first arrived in my LYS almost 25 years ago. A friend took it with her to Elizabeth and Meg's camp that first summer and, as you can see, it is very special indeed.