Hi,
I actually don't think that you really need the 2-tier affiliate system. Why? Because most of your JV partners or affiliates will promote your product to sell... and not to sign up additional people to promote. In this case, I think that you should put your efforts into somewhere else - building relationships with fellow members and other JV partners, refining the salespage to convert the best and etc. If you have a good product, sales letter and have really good JV partners that you can trust - it will be enough for you to succeed with your product launch... Even with 1-tier affiliate system.

Have a nice day,
Egidijus