Im also new to the site and interested in doing a camper conversion using a Transit for the base. Would be great to hear from others on the site who have done it or are going it.
In the meantime, I noticed a place in Oregon, Gresham Ford, that has done a conversion and its currently for sale (not sure for how long): http://www.greshamford.com/en_us/unitDetail.asp?Unit=317017 Theyve also posted a Youtube walk-around of the finished product.
Also, found a site that offers lots of advice about conversions: http://www.campervanlife.com It is a UK site and since the Transit has been around over there for a while there is more experience with it. The site also has a link to transit conversions for sale (could be good for some ideas): http://www.campervanlife.com/ford-transit-campervans-sale
On the towing issue, there is a good discussion on this forum at Cargo, Hauling, Towing & Upfit Packages. Don't know why Ford is cautious about recommending towing with the US edition when the same model sold in Europe has specific towing recommendations.