MB.advise is free and entirely optional.
But it is also intended to not only address the thread-starter, it also gives casual or interested readers a balanced look at a project idea.
Searching "bike trailer" not only brings up THIS thread:
http://www.motoredbikes.com/showthread.php?t=24382&highlight=trailer
At the very bottom of that page are 5 more similar threads, including one from spunout in the buy/sell category.
I looked into such a request a couple of years ago, and was merely passing along the "Bicycle Helmet Safety Institute", "Should You Take Your Baby Along?" advise I found back then.
For instance, they are banned in NY.
http://www.bhsi.org/little1s.htm
Most parents have no idea how rough a ride it can be in a trailer. The wheels are directly under the passenger, so bumps are transmitted more directly: one inch rise in wheel = one inch rise in trailer. The same analysis applies to a child carrier that is located directly over the rear wheel of a bicycle. We have no idea how hard can you jiggle a baby's brain without provoking injury
As a trained researcher, I found your conclusion that the AMA article "Tykes and Bikes" found that trailers are safer than carriers somewhat misleading. Carriers are indeed involved in substantially more accidents, but there was no weight given to the relative popularity of trailers and carriers, hence no conclusion can be made about relative safety (i.e. carriers may be far more popular). Safety also is a matter of severity of injury, and the article found that trailers have a much higher incidence (33% vs. 5%) of severe injuries (i.e. those requiring hospitalization). This is probably because trailer accidents are more likely to involve cars (33% vs. 9%), although it may also be because children in trailers are less likely to be wearing helmets. In any case, the article concluded that the same number of hospitalizations were required regardless of method of transportation. If carriers are used much more than trailers, then one could conclude that carriers actually are safer in terms of major injuries. Of course, as you say the sample size is too small (and biased) to draw any firm conclusions.
Like I said, advise is entirely optional, but I would hate to invest $700 in a rack mount system to find the 2-cycle decibel level gets you in a bind with park rangers.
And while considering about rack mount possibilities and solutions, some casual reader might think about buying a multi-speed tandem bicycle built for two, putting a rack mount 4 stroke (cleaner/quieter) on the back. All's you need to order would be a longer throttle cable.
Then there are the MB.einsteins, who read these threads and go supersonic.
e.g. I saw on the news an Kentucky couple built a bicycle built for 5, and are touring the country on a $300 budget.
http://bikeblog.cyclingaroundtheworld.nl/?p=234
It’s no ordinary summer vacation. Imagine loading up the family for a 7,000 mile trek from Kentucky to Alaska. but not in the mini-van. On a bicycle built for 5. The Pedouin family is already on their way.
“Well, why? Because so many people shelve their dreams and we’ve had a dream of traveling. And we’re just blue collar folk and uh, I had a small business doing home repair and remodeling and still keeping very busy despite the downturn in the economy. And we just talked to a lot of people and they got old and never lived their dreams. and we love to do our dreams, and my wife loves to ride bikes and so we put it together, why don’t we travel by bike. and we’re going to fairbanks because I was there for 2 summers and enjoyed it and she wants to see what it is like,” says Amarins of of the five on the bike.
There are enough MB.geniuses on this forum to do something inspirational like this, somebody in Arizona put a hammock in the back section of a MB.tandem, iirc.
Anyway, good luck whatever you choose.