Nice totes would be easy and likely popular. Also those "I Spy" bags for kids. You sew a bag with a clear vinyl window and add those little clear beanies and a handful of tiny toys. Make a list of the toys and the kids have a ball finding each object. It keeps them occupied for along time.
Easy to make.
Also making totes our handbags out of leather jackets or used things you find at a thrift store can be fun and make a unique product.
Placemats with matching napkins, pot holders, table runners. I'm not much of a seamstress so anything square gets my vote with no zipper!