I've actually used straw to insulate a wall. I put 1 inch mesh chicken wire up on one side of the wall then put a 2 ft tall strip on the other side, stuffed it tightly, using poly bale twine to hold the two sides together at several points as I was stuffing. As each section was finished I added 2 more feet, lashing the two sections together. (Kind of like sewing them with bale twine.) Once the entire wall was done, I plastered two+ inches of adobe/straw plaster on each side. If you are using some sort of sheathing such as OSB on one side, use the chicken wire on the other and put nails in at intervals on your sheathing to tie the bale twine to. You will get a gently curving wall that is quite nice to look at. The tighter you get the bale twine and the more points you tie, the less it will curve.
Sorry no pix, this was in the pre-internet days and I didn't think to take photos.