Smart Contracts themselves can function as products of labor. These would allow things like shares of profit to be created based upon some other members assets. A member of a fund may decide to sell shares of his profit so long as he is a member in a fund. Another example could be a quest reward that is provided in installments vs an instant reward. Contracts that are used as Products of Labor have their inputs defined and are limited to what the buyer and seller have permission to control within the network.