How Many Checking Products Should Banks Offer?

Just as manufacturers of everything from cereal to shampoo introduce new versions of their products — as well as eliminate others –banks do the same. I am looking for bank marketing officers as well as bank consultants to talk about how/why they have introduced a new checking product. And, the piece will look at how many products are too many.
Again, I’m looking for marketers and consultants to comment on this question, as well as what marketing challenges there are to eliminating a checking program. Requirements: I am looking for consultants to banks, large, mid-size or small. I’m also looking to talk with marketing officers at banks.