So you know I had to make one. I think I'll have to make a few more for frequent resting places. But ingenious, eh? Thanks to this site: http://www.dognamedbanjo.com/2010/10/27/one-woman-sweatshop/
Unfortunately no tutorial, but you can kind of get the gist of how.....
I filled mine with rice thinking that it would be a good weight. It worked, However I would suggest NOT using stretchy fabric (I forgot this fabric I used stretches)and stick with regular fabric so that it holds its' shape pretty tight.
But how cute is this?