Technical Aid to the Disabled NSW, have expanded their Freedom Wheels program to supply specially modified bicycles to disabled cyclists. The program is mainly for children, but also supplies adults with a disability which makes riding a normal bike difficult.
TAD have developed a set of standard components which are custom fitted to a bicycle to suit the rider. TAD fit a set of outrigger wheels (similar to trainer wheels but heavier duty, with springs and removable) to the bike and any back support needed.
TAD NSW are planning to make the program available across Australia through the TAD organisations in each state. TAD is a non-profit organization which accepts tax deductible donations to help its work (I gave them the royalties from my first book).