Never heard of anything like that in the US, but it wouldn't surprise me to hear of someone trying to pull something like this. Is it both ways? Do they have to pay you if they break the bond?
The closest I've seen is a minimum term for sign-on bonus, school reimbursement, or moving bonus. Work less than X months and you owe the company back either. But just minimum employment term for start-up training? Training new employees is just part of the cost of doing business and the risk of them jumping is just part of doing business.
I'm sure there are US companies that try it, though.
nope, even if they break the bond and terminate you, you still pay!
Then I have a great business model for Indian entrepreneurs.