We had a situation where a house the was funded by our Urban Renewal Authority, and based on required flood plain base elevations, the foundation was elevated almost to the point of Mark's last picture. Over 7' rise from sidewalk to garage floor, in 25'.
After dealing with for a year, a north side elevation to boot (Northern Colorado), they decided to demo the slab in the garage, and drop it 2'. We rolled the dice and allowed it, even though technically, in an unheated garage, the frost depth should had stayed at 30" on the inside also.
It has been 5 years or so, no problems, still a steep driveway, but better.