Industrial robots are heavy and thus expensive because they lack visual servoing. Heartland robotics plans to bring out a lightweight low cost robot this year. Also, the predator algorithm invented last year can do real time visual servoing that wasn't possible before. Add in a person to cover in the gaps and you might be golden.

If the above is true, why hasn't it been done you might ask.

I might be wrong, but you could have the said the same thing about why a search engine that didn't suck wasn't around in 1997 - why didn't microsoft, or yahoo, or ibm have that, or even buy it from sergey and larry?