As best i can tell, I have played the following courses that are attributed to Hills (though as noted previously, many of them may be more the product of Keith Foster or someone else working in his name):
Heritage Highlands, Tucson, AZ
Quail Creek, Green Valley, AZ
Camelback Padre, Scottsdale, AZ
Stonecreek, Paradise Valley, AZ
Heritage Eagle Bend, Aurora, CO
Tamarron, Durango, CO
Legacy Ridge, Arvada, CO
Walking Stick, Pueblo, CO
The Legacy, Las Vegas, NV
Of those, only Tamarron and Walking Stick strike me as interesting sites, and I would also be inclined to qualify those as my favorite of the courses I've played. Many of the rest are fairly typical housing community courses and are pretty forgettable as so many of those courses tend to be (which I have come to believe is almost the point).