I've wanted one of these for a couple years now. You can put THREE children in there! There are very few options for these in the states. Clever Cycles in Portland sells one. 
Here is a bakfiet in action. Nice, right? What a great way to get around without a car! Of course, this is more practical in San Diego... BUT, if someone were to give one to me i wouldn't complain! Seriously! And I'd ride it around with your logo on it every day! Of course, if we are talking practical we really should get one like this one below. Haul the kids AND the groceries!
Now, for looks, you must get a Madsen bike, though I think they only have belts for 2 kiddos I just discovered they sell additional seats so you can put up to 4 kids in there!!
Photos from Clever Cycles, Mark Stosberg, The Dutch Bicycle Co., Madsen Cycles
