I have been told by UK members of the Tricycling Association That Ken Rogers is still building trikes. I haven't been able to verity that information. A few months ago when I needed axle cones for the rear axles I had to go to Bob Jackson for parts. Their parts are the same. I think that they may even be made by Mr. Rogers or his supplier. Ken Rogers never replied to my letters at that time. In 1974, when I had my trike built, he also made trike conversion kits for less than $100 USD. I don't recall the exact price but I do recall buying about 10 of them and reselling them for $110. I made a modest profit that helped to offset the cost of my trike frame. Holdsworth also sold trike kits at that time. I will second much of what Brian has said about trikes. They are fun, great conversation starters, and challenging to ride in the beginning. The wheels are a challenge to build but otherwise no problem. My wheels are 28 years old and still true and original. It eats rear tires though.
Paul Patzkowsky Longmont, Colorado