So sue me. It turns out I did not invent fatherhood, and Daddy Types is not the first search for gear for kids.
Kid Size: The Material World of Childhood is an exhibit at the Wadsworth Atheneum that explores three centuries of objects from around around the world designed for children. The show includes a 19th century Chinese bathtub and African sleepmats, Prouve schooldesks and seemingly the entire children's line designed by Ray and Charles Eames.
My pick (until I get up there to see the Gerrit Rietveld rocking horse, anyway) is this Eames mechanical horse, which would lumber forward as a kid swayed side to side. This thing's too rickety-looking to get through the legal department of any manufacturer today, but it's pretty cool.