[sorbus]

I'm hesitant to put an exact figure on how much that would cost, but, including all the RnD that you would need to get even a basic working system, I would say upwards of 1 million. To get something that would work well (not requiring frequent modification to keep it running) and be somewhat realistic, anywhere in the region of 15m to 50m. Once the first one was running and you could just duplicate the design, I would guess that parts and assembly would cost around 100k.

If anyone went into this project with less than 1m to spend, I would be skeptical of their success even if they weren't paying for labor - this is something that would take perhaps dozens of prototypes to get perfect, and the cost would add up quickly even if it was very modular.

However, that's just an arm chair estimate. It's not my field of expertise (I'm not an engineer), and it's quite likely that a committed group of people could pull it off for much less.