Camelias? Would need pruning, but can be kept down to size easily.

...do you like Conifers? there are several available to you, and I believe hardy in your area that are very slow growing, although of course they never stop growing, but are easily pruned when they've reached a suitable height.... and this can take a number of years.... here are a few of my favourites.... I've had these for 6 years.... the tallest is Thuja 'Smaragd' (Emerald).... sllimline and slow, but you can cut the top off when it's tall enough... mine is now 6 foot.

...this is even slower and narrower.... Thuja 'Brobecks Tower'...

..Chamaecyparis 'Van Pelts Blue'... a gorgeous slow growing blue-y... and quite narrow... also tolerates drought well...

...you may not want these, but I think you have lots to choose from, if you look around....

Those are beautiful! Would you happen to know if there are any conifers with a more wide profile? I am sort of looking for something that is short and fullish...if that makes sense. Or that I could keep short and full, anyway.

..Thuja occidentalis 'Rheingold' might suit your purposes there... it has some lovely colours to it.... see what you think....