Oh, there's a Russian River in Southern CA? I was thinking Guerneville.
The only thing I can think of that would suit your purpose is a Privet but, everyone on this forum is going to yell at me for making the suggestion. If you just wanted evergreen with attractive foliage, it might be easier. Then I would suggest something like Golden Euonymus. Almost anything can be trained as a topiary. Maybe find something you like and then ask us if we think it would be a viable option.
