Where Can You Find...

there are some on etsy.

Make one from fabric. Shouldn't be too hard if you sew. Or know how to glue neatly. Get an extra crib sheet that matches the room and use that fabric. Or extra curtain that matches. Go on craigslist and search for services. Advertise for someone who sews and pay them to make you one. It would be a cute idea! Hadn't thought of that myself, and now it gives me ideas!

Make one-Buy the fabric to match the nursery. Hem it top and bottom and attach it with velcro. Use washable fabric that has been preshrunk.

havent read the other posts try etsy or ebay

Here's a company that makes them: www.diaperdress.com

You can probably get one made on Etsy for cheaper and have more choices.

What about just getting some foam crafts from a craft store that matches the theme of the room. Like flowers and butterflies or cars and trucks. Get a glitter glue pen and get creative.
Good Luck and have fun