It would be truly tragic on all sorts of levels if someone managed to make a vitamin-free reprap out of lego before the offspring of Darwin et al managed it. Can’t see it happening in a hurry though… or more accurately, if/when we get to a point where a 3D printer or CNC router can produce shiny plastic things to the same engineering tolerances of Lego… then the world will truly have changed. Big time.
Lego-Based Copy-Monopoly Liberation 
3D Printed Lego Blending
Legoification of Open Hardware
Brain The Size Of A Planet
Lego Biotech Bot
Tech-Convergeance. The Perfect Storm(trooper)
Bless. A Lego Segway
Phone-Brained Lego Rubiks Cube Doer
The Escape of the Lego Virus
On Addiction
And The Void Mooned Back...
The Spirit Of The World
A Machine to Steal Souls
More Anti Digital
Thync
Robotic Sensory Loops and Whatnot
Cartestian Robot Roundup.
Post-Scarcity Link-Dump
Servo Bender
it would be impossible.
to make lego parts (like gears) with that tolerance, you need higher precision mechanics than lego. that’s it.
I’m playing with the idea that you might be able to get around low-tolerance hardware by using sensors that allow the system to re-calibrate 1000 times a second.
I mean we somehow managed to go from stone-tools to gazillions of transistors on a microchip the size of a (little) fingernail. Impossible isn’t always as impossible as it looks.