The Lenny Lamb Onbuhimo is an onbuhimo designed for back carrying. It is made from a Misty Morning blue and grey wrap conversion and has perfect fit adjusters. Suitable for babies from six months and up
Here is a good video for a back carry with an general onbuhimo
There are more videos and photo tutorials listed on the Carrying Matters website.
The Sheffield Sling Surgery website is here - full of useful information about safety, all sorts of articles about warm/cold weather carrying. knee to knee support, big kid carrying and so on
Facebook page is here and the online support group the Virtual Sling Surgery is here