Equity vs. Profit-Sharing

One of the most difficult business structure issues to be resolved in cooperative, mutual or producer groups creating “legacy” assets is that of transient employee/owners. Say for example you want to have a worker-owned co-op that produces a software product.
In the “normal” producer co-op structure, such as a farm products group, the amount of goods you contribute determines the amount of your profit-sharing. If you generated 200 bushels of corn, and your neighbor generated 2,000 bushels, you would each get a proportional profit-share.
Similarly in the consumer co-op model, a patronage refund is distributed in proportion to your purchases. If I bought $500 worth of groceries, my refund is 10% of someone who bought $5,000.
But in the case of a software product or any other enterprise where there is a persistant asset, what happens when one of the producers/workers/employees/owners leaves the firm? What happens to their equity investment? The problem is that the product will continue to generate revenue (or interest) for years, but if you were to continue to pay them at the full rate of their previous profit-share, there would be no incentive to stay with the firm. In other words, they are not producing anymore, but the asset is. What is an equitable arrangement?
I think this is particularly difficult in software, where early contributions are typically much more “make or break” than later contributions. An excellent first engineeer can set the stage for years of productive growth. This employee has much greater value (to the business success) than a later employee.
(My philospohy is that all people have equal human value – I am commmenting here on the economic contribution to a collective enterprise, which in my view varies by experience and education, at least. This isn’t a socialist model but a collective determination model.)
A separate but equal problem is attracting investment capital, since typically worker-owners don’t have a lot of cash sitting around. I’ve heard of a hybrid LLC/co-op that I’m researching. Details when I know more.
One solution I’ve thought about is something along the lines of how physical assets are depreciated over time on tax forms. in other words, the percentage of profit-share might decrease over three or five years by equal percentages. I’m no expert here, and perhaps this is a solved problem, but I haven’t come across it yet.
Another approach from the standard stock-ownership models would be restricted stock. I am particularly interested to see what the details of Microsoft’s restricted stock plan will be – they are eliminating stock options for employees and granting restricted stock instead. What exactly those restrictions are will be a helpful example for developing incented, humane, locally-controlled governance structures. Not that MSFT is any of those things, but we can learn from their expensive legal help.
I would like to collect contracts, operating agreements, state incorporation papers, etc. related to cooperative, mutual or employee-owned businesses. Sharing this knowledge will help speed the evolution of prosocial and progressive business structures. I am willing to maintain confidential and anonymous contributions. Please pass along anything you might have access to. For complete anonymity, photocopy docs and mail them to PO Box 828, Hanover, NH, 03755.