Google 'small travel trailer with bunks' and a lot of sites come up. Some even have a bathtub which would be ideal for little ones. Here are a couple sites. Then start looking for used ones in RVTrader, etc.
http://www.rvingplanet.com/rvs/travel-trailer/bunkhousehttp://www.jayco.com/tools/archive/2015-jay-flight/23mb/I think with this type you'd really use it a lot and it's perfect for a small family. You'll probably be looking at a 23' one although you might find a shorter one. The bottom bunk could easily be a crib for the first baby and could be moved upward when the second one arrives. :) Bunks give children their own space and can be put to bed early without disturbing the parents. Also, bunks are nicer than converting a table into a bed every night and finding room for the bedding. The table is in the center of the room so no easy parent time.
