I recently heard about a startup that automatically routes purchases to the user's credit card that would give the best rewards for that category of purchase. They somehow act as an intermediary in the card processing chain, so the transactions still show up on the final destination as originating from the merchant, not the routing service.
I don't recall the name, but it seems plausible that a bill consolidation service could do something similar at a similar layer of the payment processing infrastructure, collect their percentage, and be profitable doing it.