We just got back from a hunt in Montana and the guide had a really great feature on his GPS. He owns huntinggpsmaps.com and he has chips for GPS units that show the land you are on as well as the property lines to point out private from public land etc. It's a really neat product and a couple other guides in camp were using it and loved it. I believe he combines land maps with Google earth and this tool is something already developed you can use.
He was using the GPS to track our way points, but he could also check at a moments notice what the land looked like and where we were in conjuction to other landowners property. I could see it being a very useful tool for guys who hunt public land out west.