[Nonfractal]

Johnno,
I'm not really interested in building these for sale,
Many have asked me to construct one for them, so maybe a slot car manufacturer would be interested if the design were reworked for external psu and safety compliance) 

Please feel free to give the designs to anyone who'd be able to make this up for you. 
For someone with construction / modeling skills and soldering skills, it's all possible, however, no one has managed to replicate this unit ( a few have tried)

Alan