I stumbled over this thread by coincidence and for Mary D and Bob Bankhead: thanks and yes I did do a follow up article for backpackonglight: http://www.backpackinglight.com/cgi-bin/backpackinglight/babyonboard_part2.html
The book was published in April 2013 in Belgium, in Dutch. No english version in sight though, sorry for that. But the article captures a lot of things. Bob: what you said in the reaction to that first discussion even made it into the book - as well as other less construcive reactions :-)
The book has caused some debate here in Belgium, with over 20 press reviews/interviews and just this weekend I gave the first whole day workshop on hiking with babies/toddlers, together with 2 experienced friends, to 40 nature enthousiast parents with doubts and questions. We plan more workshops as we had full subscription so you can say there is interest in this here in Belgium. Anyway, I enjoy reading about the reactions here and let's work together in inspiring all those hiking-parents out there - in the interest of small children...