While I haven't (yet) had to do a funeral for someone who hated flowers, we did do some table centers this week for an event -- for people who hate flowers.
Our solution was simple -- cylinder vases, glass chip stones at the bottom, dried reeds straight up the center, and a big swoop of bear grass. The head table got a different arrangement -- a long horizontal glass tube with holes in the top (I call them flutes), and a dracaena reflexa stem (Song of India) in each hole. They loved it. Easy $$$ for us.
Recently, we did several funeral pieces for a man who built boats. Although he loved flowers, as did all the people who ordered for his funeral, one of the pieces we did was a punt (a type of small boat) fashioned out of chicken wire and sheet moss. Then we positioned his favourite brushes, hammer and other tools inside. It was quite a hit.
I think the trick is to "think outside the box" -- look around at all the things you have in the shop that are not floral. Think of how they could be used.