We have a little Juniperus chinensis var. pyramidalis which doesn't get very big and looks nice but it is very spiky!

do you get very cold winters guest because if you leave the pot out the frost can reach the roots through the sides ( in the ground they are protected) pots can be insulated or moved for winter but it needs to be decided as you choose your tree. I've bamboo in very large plastic pots inside decoratives which seems to help, I've also an Acer 'flamingo' but they need copious amounts of food, water and care--more than in the ground---