I have the same dilimma for the Kids' Chaise Lounge Chair, which is now out of print. The company "Maudlin Shore" is evidently non-existant now and those pillow forms are NOT standard sizes. I've searched all over the internet and cannot find any pre-made for the sizes I need. (McCall's Home Decorating 4120 pattern)
So it looks like I'm going to have to make my own!!!