I LOVE eBAGS!!!!!!!!!!!  I bought a suitcase for myself last year and fell in love with the velcro movable compartments inside and the bright colors.  Lots of pockets.  So, since my children were big enough to need a small suitcase I began searching and of course, eBags had the solution.  This is amazing because it has backpack straps (that can be tucked inside if not needed), allowing the kids to carry their own luggage, and a duffle bag strap as well.  This bag is also expandable.  Has lots of pockets in all the right places.  The quality is perfect.  Tough.  Big heavy zippers.  It is an adult size backpack, but manageable for a large 4 year old.  Best luggage I've ever owned.  Price is unbeatable.