Why not look at a Camamile lawn? Or Hypericum Reptans (St John's Wort) is a lovely carpetting ground cover evergreen plant with yellow flowers in sommer.

Prostrate forms of juniper or rosemary?

Even ivy and just keep it strimmed back a bit. A friend has a section of his garden covered in a variegated ivy. It smothers weeds, so far it has been no bother to keep back. My brother in law tried the hypericum on his bank and the weeds got through it. In the end he had it done with caged stones. Expensive or what? Maybe plant some bulbs in amongst to add interest in the spring.

How about winter flowering heathers (ericas)? They come in lots of different leaf shades from gold to dark green and do not need very acid soil like the summer flowering callunas. They would need weeding for a year or two until they spread out and join up but should eventually be trouble free. They would go well with a prostrate juniper - I have this combination on a bank I was tired of strimming.