What age can you get kids in a Christiana bike? I'm thinking - expense aside - it is way better to carry the kids in front, rather than behind you. Those kiddie trailers give me the heebeegeebees - if people cycle like they carry wheely luggage at least!
bit expensive but:
http://www.mothercare.com/Taga-Stroller-Bike-Red/dp/B0028XFJWG/sr=1-55/qid=1249402543/ref=sr_1_55/280-6026427-9426403?%5Fencoding=UTF8&m=A2LBKNDJ2KZUGQ&n=42803041&mcb=core