stroller costumes

stroller costumes
I need some ideas for matching brother and sister costumes. ?

My children are two 1/2 years apart and I've managed to get them into matching costumes for three years now. But, I'm out of ideas and need something that will float with my son. My son is 6 and my daughter is 4.
Their first year he was a daddy and she was twin. She was born sept 11th at 3lbs and wore baby doll clothes for three months. So I dress her and a doll alike and pushed them in a stroller as twins. He wore a hat and tie as the daddy. The nest year he was a cowboy she was a pony. Then they were pirates, and last year a prince and princess.
Any ideas?

Lazy Town

http://www.juzcostumes.com/costumes/lazytown.html?for=baby

Dora The Explorer

http://www.juzcostumes.com/costumes/doratheexplorer.html?for=baby

Doodlebops

http://www.juzcostumes.com/costumes/doodlebop.html

Looneytunes - Sylvester & Tweety Bird

http://www.juzcostumes.com/costumes/looneytunes.html?for=baby

Over the Hedge

http://www.juzcostumes.com/costumes/overthehedge.html

Sesame Street

http://www.juzcostumes.com/costumes/sesamestreet.html?for=baby