I think you're on the right track with your original idea. Winter Gem Boxwood would grow well and be neat and tidy.

I'd plant herbaceous perennials in front of the hedge for color. One of my new favorites is heuchera 'caramel', which keeps its leaves and color through the winter here.

In Maryland, I'd expect a good percentage of the houses would have either rhododendrons or evergreen azaleas as foundation plantings on the north side. Just take a few walks and look. If people are out working in the yard you can ask if they know particular cultivar names.

Many shrubs can be rejuvenated and reshaped. I think I'd want to know what I now had before I started digging.

Evergreen azaleas would do what you want.

I am in love with winter gem boxwood, though. Compared to them, all other boxwood is an enormous disappointment.