That's really cool that you're able to bike around with the kids that way. I've never seen a bike like that before.

That monster is called the long Haul, and it's handmade in Eugene Oregon.  The company, Human Powered Machines is part of the Center for Appropriate Transport. (That's Rory and I on the front page of the catalogue).

They built the box-bike (called a bakfiets) with a bench seat in it.  For Julian. we bolted a baby-seat onto the aluminum foot-plate (took 2 u-bolts and a drill...about 30 minutes). It works just like it would in the car, except it doesn't come out.

The downside?  WITHOUT the kids, it's 60 lbs.  Ugh.