We needed a promotion based on the number of items purchased from the same manufacturer. With the default promotion modules we were able to let dollar amounts that would trigger a discount, but the total would not distinguish between non promotional manufacturers vs. promotional manufacturers. For our needs, the promotion was a 10% discount when 3+ items were purchased from the same manufacturer. I had previously posted this solution in the Configuration thread about this discounting need, but this modules would be more appropriately posted here. You will see two "QuantityDiscount.java" files: one is for the konakart package, the other for konakartadmin package.
These are fully functioning with my konakart v22.214.171.124.