I have the same situation and put two mother-in-law tongues out there and they are very happy. The get to be about 3-4 ft. tall.

What about a bamboo in a pot? Get a clumping one. You should be able to find something in the height you want, and I think they always look stunning in a pot near an entrance. You'd probably need winter protection in your area. A garage might work but check into that first...

You might want to consider house plants -- there are several nice ficus plants that would do well in that kind of light, for example -- or a Norfolk Island pine -- or any of a host of others. That bright, indirect light would be great for a lot of plants.

If you want something hardy that you don't have to protect in winter, check with a local nursery. They may have some good ideas, although a plant in a pot is going to have to be really root hardy to get through the cold in zone 5. There might be an evergreen that would work well (and you could put lights on it in winter) :) -- just be sure, whatever plant it is, that the roots in an exposed pot would be able to take the cold.

Have fun!

How about a hosta "Krossa regal"?

what about an obelisk on top of a pot- with ampelopsis varieg growing up it?in sun they get bad jap beetle but not in shade. lots of nice bright variega and beautiful blue and pppl berries in fall.
i like carolann's bamboo idea. the yellow and grn stripe one(extremely invasive in the garden, but fine in a pot) would accept the shade; you could plant it on the outer rim of a big glazed pot, as a fountaining edge, and then plant a tall thin evergreen in the pot middle.likewise you could use the lower growing, shade-tolerant, container planting- through- the- winter-tolerant hakonechloa.

schefflera elegantissima (formerly dizygotheca elegantissima) would be lovely, but it will die at 35o or lower. It looks like you are up North, so you'd have to winter it over somewhere so it wouldn't freeze. They are tall and narrow. Do a Google Image search if you want to see what it looks like.

I've had a great deal of success with cannas.

And that's in zone 5 with a north facing recessed porch.