You could get in touch with the nice people at this bike co-op
Don't forget the Rochdale Principles of Cooperation. They may not be the legal stuff you're looking for, but they're the bare bones of any cooperative endeavor, IMO.
Original version (1844)
• Open membership.
• Democratic control (one man, one vote).
• Distribution of surplus in proportion to trade.
• Payment of limited interest on capital.
• Political and religious neutrality.
• Cash trading (no credit extended).
• Promotion of education.
ICA revision (1966)
• Open, voluntary membership.
• Democratic governance.
• Limited return on equity.
• Surplus belongs to members.
• Education of members and public in cooperative principles.
• Cooperation between cooperatives.
ICA revision (1995)
• Voluntary and open membership
• Democratic member control
• Member economic participation
• Autonomy and independence
• Education, training, and information
• Cooperation among cooperatives
• Concern for community