There is such a nice pillow made from satin in the April 2011 issue of Quilter's World. The pattern isn't in the book, but you can access it online. Use the address: QuiltersWorld.com/EXTRA. Use the limited time code: QQ9283 You can get the instructions and print them off. This will only be available while this issue is on the news stand, so I suggest you look at it and if you like it, print it off and you can make a decision later.
I have made pillows from bridesmaid's dresses, in which I used the fabric, with the trim still attached to it, to decorate the pillow. They have all turned out well, and it keeps the integrity of the original design of the trim embellisment.
I hope you find something that you like. I think this is such a beautiful way to remember the day and to honor your sister and her husband.