Certain types of bridges and other structures sit upon a pad of rubber , oddly enough called a bearing rubber. LOL Contact ( Google it ) a bridge Bearing Rubber supplier near you ( Redwood Plastics, Heava, Canada Rubber Group, are some of them in Ontario , ask for sales ) They will likely be able to cut you one from some of their sheet goods. You can drill whatever holes you need with speed bores and twist drills. It comes in various Durometers, may even be willing to make one out of polyurethene for you. Rick