Below are some of the features we are interested in - some where mentioned by othellotech
Commissions should be on a scale (as mentioned by otheotech. Currently we do this manually:
ie:
1-10 active accounts = n%
11-24 active accounts = n%
25+ active accounts = n%
This should be on the configgeneral.php area.
When setting the Products/Services in configproducts.php > Other: you could have radio buttons to choose if the product / service is part of the 2nd+ tiers, as well as the options that are currently available. This will assist in low margin items such as Dedicated Servers, Domains, Dedicated IP Addresses, Memory Upgrades, etc, while maintaining higher commission rates for products / services like Shared Hosting. A maximum 2nd tier commission should also be available.
2nd+ tier commissions should also be on a scale and should have the option of paying Affiliate #1 either a % of Affiliate #2's sale or a % of Affiliate #2's commission.
ie:
Say Affiliate #1 is at a 25% (3rd level) commission structure because they meet certain criteria. Affiliate #2 is at a 20% (2nd level) commission structure:
Affiliate #2 sells a $10 hosting plan - Affiliate #2 earns 20% or $2.00. Affiliate #1 can earn either a $2.50 (25% commission), total cost to merchant in commissions = $4.50. Or, Affiliate #1 can earn 25% of Affiliate 2's commission, or $0.50, total cost to merchant in commissions - $3.00.
With commissions being on a scale, the system to should recognize any manual increase in an Affiliates commission "level" and calculate based on the manual commission entered in the Affiliate's profile versus the criteria established.
ie:
Affiliate may not have 25+ active accounts but they may have a higher commission structure.
Bonuses: No bonuses paid to 2nd+ tier affiliates should be commissionable to prevent affiliates signing up fraudulently to receive additional commissions.
I'll add more thoughts as they come to me.