I don't use a rest now, I use a bipod and sand bags, but I am thinking about getting the Caldwell Lead Sled DFT Rifle Shooting Rest. Runs about $190 and I think it has fairly fine adjustment (I have never used it though). But if you are looking for a really rock solid rest, you may want to look into a two piece, unless you want the rest to take up the recoil.
good luck.