Down there I would use one of the suitably sized Bambusa multiplex cultivars or something else more interesting than box or Japanese spindle - there are probably multiple region appropriate candidates. Also the box won't be faster than the holly, and boxwood blight is being seen in Oregon so it is probably in California also.

Try making some visits to publicly accessible gardens as well as independent garden centers for ideas.

http://www.bamboo.org/BambooSourceList/BambooPlants.php?G=60&Dv=+&Hv=+&Tc=<%3D&Tv=+&Sv=+&C=&M=1&Button=FIND&U=I&S=1

Thanks. I thought about clumping bamboo, especially the Green Panda variety but according to this article (http://www.mnn.com/your-home/organic-farming-gardening/stories/why-you-should-not-plant-bamboo-in-your-yard) "The problem is that even clumping species spread, albeit not as vigorously.".

Again not necessarily a suitable kind down where you are. Not really the right shape either. Tight clumpers like these have the new shoots coming up very close to the previous set, in the manner of an iris or hosta. They never travel feet or yards at a time, to come up by surprise some distance away.

Does it have to be a shrub? Would a vine on an obelisk do the job?

Is pruning out of the question? Pittosporum tenuifolium 'Sliver Sheen' or 'Tasman Ruffles' are more suited to your climate than the box or euonymus and will grow considerably faster as well. Will get larger than you want but both can be pruned to size and shape easily.

Podocarpus can be pruned, also. And is fast growing. Check out P. gracilior (there are others that are slightly more interesting and less common but this will give you an idea).

Pruning is not out of the question but I prefer not to prune the tops, as I want it to be 7ft-10ft tall. I was also looking at a wax leaf privet but it looks bad when it is pruned to 2.5ft wide that why I was focusing on narrow hedges.

I also prefer a standalone vs a wine which might not go taller than the 5ft wall I have.

I did some research and it seems like Orange Jasmine might be good for my zone although it might not look good at 2.5 feet wide.

Is it ok to plant Murraya paniculata where you are.? I believe it is invasive in some states.

Thanks. Lavender Starflower looks promising. I also found this slim bottlebrush: http://shop.monrovia.com/callistemon-vim-slim-tm.html