Thank you all for your votes -- after carefully considering all the options, Joe and Dave chose Drifting for Ruby's second birthday.
On Saturday I went to my LYS for the yarn, and was, to say the least, quite keen to get going.
I'm loving this knit. It's so cute. The colours are gorgeous, and it will be so toasty warm. What I DON'T understand is, why is no one else on the interKnit making this? I was doing some Google-fu and couldn't come up with a single project. Ravelry is completely Driftless too, and in fact the design is not even listed as one of Inspired Fair Isle Knits' projects. It's very weird.
It's knitting up fast. I am almost half done the front, the back is finished (but it's a little bit bockety and I may redo that piece) and the sleeves, being raglan, will come together quicker than either of those.
I did have to do a little yarn sub for the blue on top. I couldn't find a satisfactory colour in the yarn I had chosen, so I used a different wool, Lanett Superwash fingering weight, and doubled it to make a DK. Knitted up, the doubled Lanett is gorgeous. The softness is incredible, the stitch quality is excellent - very balanced. I've used this yarn for a couple of things before, but the more I knit with it the more I love it. It's sold as a baby yarn, but the colour palette is impressively varied - not just pastels.
Anyway, it shouldn't be too long before this is an FO, even taking into account the probable reknit of the back. I'm not exactly sure of Ruby's birthday, but ideally I'll get this done, blocked, seamed and mailed by the third week of August.