I have never seen a book that can cover all the different scenario`s. I am wondering, are you setting up exclusive distributors, or exclusive manufacturers rep agents?
The distributor would be buying, stocking, and reselling your product, where the rep agency would only be attempting to sell your product for a commission of the sale.
Obviously, if you have distributors who want to purchase and resale your product, then the only problem you have there is deciding the minimum they would have to purchase in order to be a reseller of your product. Limiting all distributors to a minimum purchasing amount weeds out the tire kickers and pulls in the real distributor. A good distributor can make your business grow beyond your wildest dreams. Be carefull about giving out exclusive distributorships. You could very easily be limiting yoursef and your products growth ability. If you have to give an exclusive, then limit the time and provide a minimum amount of units that must be purchased during that time frame in order to continue being an exclusive distirbutor.
Now, if you are talking about rep agents that want to sell your product for a commission, then you have to be more skeptical. A good rep firm can help grow your business, though if your product is not their number one product, they will tend to spend more time on the products that sell the best to the customer base they are familiar with. Many rep firms want exclusive rights to certain territories, and they want to be paid the commission on the sale no matter who brought the business in. This can be quite hard to do when you know your the one who sold the customer, though your having to pay a commission to someone for doing absolutely nothing. This is why you have to be very carefull. The best rep agents will be willing to market, stock and ship your product from their warehouse, while you handle the invoicing of the customer and collection of the payments.
I am not a lawyer though my understanding of the law is that anything written and signed by both parties is legal binding on both parties, though both parties must have a way of getting out of the contract.
I hope this helps...If I knew your product, then could probably be more helpfull.