Tim,
Although my remark was casual, it was based on my own experience. I know the acreages of my courses, and it is a struggle to get one on less than 200 acres these days, whereas 10 years ago, we could get a course on 160 acres. The difference really is in the fact that most sites have an abundance of "off limits" areas. To be fair, if those areas are wetlands, they aren't off limits 100%, because they can be located between holes where distance buffers would exist anyway, or incorporated as forced carries. Thus, 50 acres of wetlands may just increase the need for land by 25 acres or so.
Assuming no St. Andrews style crossing fairways, most golf holes have a dedicated corridor of 225-300 feet. Thus, every hundred yards of golf course adds between one and two acres. (300 feet length X 300 feet width = 90,000 S.F., about two acres)
Yes, the corridors are a bit skinnier by the tees, so it may not be a full two acres, but it will be close, so a 7600 yard course will require at least 20 more acres than a 6600 yard course, assuming equally efficient use of the topography.
The financial impact of more land comes usually more in the housing type course. If you are building more parallel fairways, the irrigation mains and cart paths can be shared in many instances, where there is a direct increase in those quantities when the course is linear. However, it costs about $2000 per acre to grade, $9000 per acre to irrigate and $2000 per acre to grass, so the costs aren't astronomical, just incremental.
Jeff