I really appreciate the idea of having a career path that doesn't involve moving "up" to management. I'm a developer because I love development, and my own personal hell is managing a team and never getting to code.
The point is that it's possible to run a company where managers don't have a purpose and aren't necessary.
This study from around 2002/2003 puts their revenues at $8 billion annually with 60,000 employees. That puts their per-employee revenues at around $133k.
http://www.stthomas.edu/cathstudies/cst/conferences/bilbao/p...
This puts their revenues at $24.2 billion in 2008, which is almost $300k per employee, if you use the ~85,000 employees figure.
http://willblogforfood.typepad.com/will_blog_for_food/2011/0...
Looking more closely, they're a strange sort of conglomerate. At a glance, I see two banks, two insurance companies, roughly two hundred industrial companies, a dozen retail shops, a dozen food-related businesses, a dozen research firms, and ten education companies.
In a way, it reminds me of Idealab, in that each new company is a new pool of equity (with the associated incentives that result from ownership), and that failures are not punished, but rather result in retraining or placement in a different firm. (for full co-op members).
It's also interesting to see that the founder was a priest who started off with a co-operative polytechnic school and bootstrapped everything from that base.
So those figures would indicate 174,000 Euros per employee, which makes a lot more sense.
if your environment has a significant amount of elements that engineers (or generally - employees) wouldn't want to be in charge for, then you are already deep into the problem and the shortest solution here is to assign managers to be in charge of those things.
The key is to not allow the situation to degrade into creating "demand" for managers. For example, once you create one manager for a group, s/he would want to talk to somebody, preferably managers, from other groups. That burden on the other groups would naturally trigger response - creating managers in the other groups. That starts to structure the information and decision flow the way that rank-and-file employees lose much of the visibility into the product and business and thus lose the ability (and motivation) to take even small decisions, thus requiring even more management ...