I suggested the American Holly without knowing height or space requirements. They are large, getting to be 25 to 50' tall and 15 to 25' wide (over a long period of time, of course). Their zone is 5B-9A. They are deer resistant.
If these are too large, or if you are not in zone 5B, you might consider the shrub form. There are many varieties, but 'Blue Princess' might work well for you. They get 8 to 10' tall and 4 to 8' wide. I think that's pushing it a bit...that will take awhile). Their zone is 4B to 8A. Add one male, 'Blue Prince' for berry pollination. The berries are a great feature.
As far as the deer go, they might take a nibble, but will spit the leaves out, as they really don't like them. This has been my experience. To be sure, your clients should spray with a deer repellent.
Here's a link to the Rutgers plant info for deer resistance. This is great....I keep it on my toolbar. I already entered Holly for you.
http://njaes.rutgers.edu/deerresista...&submit=Search