How do we honor a deceased coworker?

A coworker who was much beloved by everyone she worked with passed away from cancer recently. Her family is not having a service for her. They say it's because it's against her wishes; that she didn't want anyone to mourn for her. However, from what we understand there were some problems in the family regarding her estate so we're not sure if that is true. Many of my coworkers want to do something to celebrate what a wonderful person she was and how she touched our lives; but if not having a service was truly her wish then we don't want to disrespect her either. We are currently talking to corporate about getting a plaque or a picture of her hung up in our store; but would it it appropriate to have a little ceremony when we hang it? Any suggestions on what we should do?