Here's the costume I made for my 5 year old daughter this year: YouTube - Transformer Halloween Costume 2008 It turned out much better than I had hoped. The leg pieces are attached to her shoes and shins, so it does not hamper her knee movement at all. The ankle attachment is strong foam (floor pads meant for a weight room), so there's a lot of movement there as well. She can run, jump, and climb stairs in them. The body is held in place with wide foam shoulder straps. There are headlights and tail lights. The headlights are wired to switches that she can easily reach in either mode. It survived trick-or-treat night, being worn at school, and a 1-1.5 mile (?) parade. It is a bit worn, but still works. Cardboard, hot glue, Velcro, and magnets make almost anything possible. Anyone else want to share?