I visited my friend who is about to start her chemo today and delivered her shawl. (I've also figured out a way to upload photos so you get to see it.
For the back I followed the pattern exactly (the Chunky Highland Wool Wrap from Elann.com) — other than not using wool of course. If I were to do it again I'd change the cross of the top left cable of the fleur de lis pattern to make it so that it doesn't go over twice in a row. I'm not sure if you can see that in this photo or not.
For the front I changed the pattern completely. The cable they had on the front pieces was very pretty but it pulled far too much in this totally synthetic yarn (Crystal Palace Puffin). Since I couldn't block the pulling out it had to go. I fiddled with a couple of more simple cables but ended up just using a stitch pattern from Barbara Walker vol. 1. I like the way it turned out. My friend liked it too. She said that the nurse told her that some people get cold sitting in the chemo chair during the treatments and it would be perfect for that. I hope it is.
I need to dig out a chemo cap pattern. I'm thinking about making one from some Sock Candy I have. I'll have to soak it in vinegar before giving it to her though, since my Sock Candy always loses its color on the first wash. I need to get a good picture of my post-wash Holey Socks to show you. It's really astonishing.