Not many. It seems to me that a couple of extra steps/machines in the production process could handle the break-in. Think about it. What is break-in really but a controled amuont of engine rotation at a certain temp to wear the parts togeather, right? Well if the engine were to be immersed into a vat of 220 degree oil and spun at a set rpm (or a computer controled variable rpm) for a predetermined amount of time - or even subject it to hot and cold immersions to simulate the heat cycle method, would that not provide the same results?
I have often thought that engine companies could drastically reduce their warranty repairs or a relitively minor initial investment.