After a bit of searching, I happened to find the Wien pattern in the Berroco Sox book 'Playground Stripes'. We were in Victoria, BC at the time, and I found the pattern book and some suitable yarn in the Beehive Wool Shop. I used DROPS Fabel superwash sock yarn for the body and another sock yarn for the hood lining.
I FINALLY finished the cardigan last month. Like I said, embarrassing. And because of my procrastination, I'm really hoping my son gets at least a few months of wear out of this sweater before he outgrows it (mostly in length). Oh, and his extra request - a red zipper! It was the first time I had ever installed a zipper in a sweater, but it was surprisingly easy. I wish I could remember which blog I used for the technique, but there are a few different methods. I basically treated it like I would a zipper installation in a sewn garment, except that I sewed it in by hand after basting it first.
Now we have to go somewhere cool so he can actually wear it!