Ian, I used the USGS DEM and other information along with the free USGS Global Mapper software to generate 1-foot intervals for my family's land. Unfortunately, they can't be exported, so I took screengrabs when zoomed in and tiled them together in photoshop. It's a fair bit of work, but it's the only way I have found to get that level of detail without shelling out some serious cash. I don't know how familiar you are with the USGS sites or their data, but if you want more detail, let me know, I can post a tutorial of sorts if it makes sense.
Edit: By the way, I wouldn't recomment 1-foot intervals if you are interested in converting to 3d, just too much information when dealing with an area the size of a golf course, unless you have some serious hardware. I think a jump to 2-foot intervals would probably be fine.