I know old post, but finally got around to doing this myself.
Angry Birds Star Wars 8", cut it open, pulled most of the foam out of it. Used a black crew sock put it in the Bird to make sure it fit. I sewed the sock to the top of the bird to hold it still. Was a bit rusty with the sewing, but ended up getting it together without a hitch. Sewing a sock has its difficulties...lol
Tip for those who try this, stretch the sock out when sewing it as the 460 head needs to slide through it. My first test sewing job was a bit to tight and I had to relieve some of the stitches.
Not a great pic, but a cell phone pic tonight of the beast.