Here is a list of the largest majority employee-owned companies in the USA: http://www.nceo.org/articles/employee-ownership-100.

That is companies that are >50% employee owned.

Companies marked with an asterisk are 100% employee-owned.

The biggest 100% employee-owned company is Lifetouch Photography in MN with 25,000 employees.

But Co-ops and employee owned companies are not the same thing.

I have worked for several small co-ops that used consensus decision making. While it is true that everyone has an equal voice the tendency is to listen more to people with more experience or expertise in the particular area being discussed. Also, there is a lot of delegation that happens where subgroups are formed so not everyone is deciding what type of toilet paper to buy or how exactly we should implement some minor detail. That being said sometimes random people come up with the best ideas, so it was helpful to have them involved.

I found consensus decision making to be a lengthy process but a rewarding one.