The Pygmy date palms might work just fine for you, nut they do need more regular irrigation and fertilizing to look their best, and if you get much below 28~29f in winter, the foliage will show cold stress. I quite like using other dwarf palms such as Chamaerops humilis v cerifera or Trachycarpus wagneriana in full sun containers. Another choice slow growing silver palm for full hot sun is Brahea armata. If you are looking for choices in a bit more wind and sun sheltered locations, palms such as Chamaedorea microspadix or C radicalis are also nice. A palm look alike to consider might include Cussonia paniculata.

I'm near Palo Alto. I quite like the C. humilis. Slow growing, and takes all the sun I can give it and takes the cold in this area.
The only bad thing is when I planted mine out, I needed some band-aids after. Got some evil barbs on the fronds, these do.
Very attractive plant though.

The Bureau capitata is also good in containers, but the spread of the canopy and size even while young will look best in larger sized pots, At least a half oak wine barrel or larger still. Transplanting a palm out of a container that has been growing for years is also a bit of work. Often easiest if you are willing to simply break the pot to liberate it. At a minimum, make sure the pot's opening is not less wide than the pot, or you'll likely not get it out without breaking the pot. Almost all of these palms are a bit thorny to prune/transplant, but for their beauty, can't hold that against them. Arenga engleri is another slow growing clumping palm good for containers with no thorns and interesting silver color on the Lear's reverse, but you need to be careful of the ripening seeds, they are a skin irritant, and the blooming portion of the palm does die after it blooms. Very slow to bulk up in SF East Bay Area conditions without benefit of reflected heat, which actually can be an advantage for a long term container plant.

Thanks Bahia for all the great suggestions and deep roots.

Since these are focal points, i don't want to risk the cold stressed foliage of the pygmy's, but its good to know you think the full sun and wind are fine.

Now I'm leaning towards tough as nails regular Chamaerops humilis, since I need some green.

Yes, the unweildiness of large visciously spined potted plants, is a bit daunting, but gotta buck up for the love of beauty.

And price.

Ok, got the chamaerops humilis, while carrying them around I couldn't help noticing all the other spots they enhance.

So, I am thinking of putting one in a built in planter which is 4x3 but only 1 ft deep. Will the roots eventually wreak havoc on the brick and concrete patio which surrounds the planter.

Or will the planter control its size? Maybe a little of both is what I am hoping.

I have been really stuck about what to do with this planter, because I want the foliage to give me some privacy, but don't want whatever i put in there to end up monstrous and looking out of scale with the size of the planter, if the roots escape.

While it might be possible for this palm in such a shallow depth planter, it wouldn't be the ideal. The size would tend yo restrain ultimate size, and the roots probably wont damage the slab, but could eventually push out the brick sides. How big of a foliage screen do you want, and is this also a full sun spot? Could things like Foxtail Asparagus or Sago palms work in this planter?

Bingo! Thanks Bahia. I would love if Sago Palm could work.

It is afternoon sun, from around noon on. The outer width of the planter from edge to edge is 50", so I wouldn't want it wider than than 5 or so feet ultimately.

I am flexible on the screen height, tall is good, but if it looks lush, that will be an improvement.

Another option is, currently cordyline "Purple Sensation" is in the planter. My original plan was see how that did underplanted with succulents and if it needed more room for a taproot, or looked gawky, then transplant it. Then I read they can be difficult to transplant if the taproot is disturbed.
I have a place in the ground I could put the cordyline, since it is still young, and I would prefer the look of the Sago Palm.

Festival Grass Cordyline could also be a good foliage filler for that planter, and I'm sure the Sago Palm would work there, as would Aeoniums 'Swartzkop'.