I have a large yard and I've started to expand from the porch to the yard with static props. I have just one problem. We live on a hill in Central Pa and the winds can get REALLY bad. Especially up on the hill. I can forget about making the usual tombstones. They'll rip apart and blow away. What I need is very sturdy tombstones and ones in which I can use rebar to plant it firmly in the ground. Any ideas?