A design from a couple of years ago that is, I think, clever as well as practical and pretty: the Changeling Travel Changing pad.
Worked in Stockinette Stitch stripes, the center panel has garter stitch edging, and the side flaps are picked up along the sides. It fastens with a button, and is designed to fit around a pack of wipes or a couple of diapers so everything you need is right at hand. And if you knit it in cotton or a cotton blend, you can pop it in the washer as needed.
This is a great project for a baby shower, as easy to knit as a blanket but more out of the ordinary.
Folded up, Changeling measures approximately 11” x 7” x 2”, and opened up, it measures 26” x28”.
You can buy the pattern at kidknits.biz in either printed or pdf form.