You have two things that you have to address...the moderate light and the plant is being given a location where air currents will affect the soil's drying.
There are ample numbers of plants that will grow 4 - 6 feet high....you didn't say how narrow.
The Musa cavendishi (banana) will grow to 6 feet and can be summered out of doors but prefers indoors.
It has leaves 2 - 3 feet long though.
It needs high humidity. Other varieties of the same plant have similar leaf growth.

The ficus benjamina can be trained to be quite narrow and will certainly grow to 6 feet high.
The pseudopanax lessonii...an evergreen is a multi-stemmed native of N.Z. can tolerate sun or shade. Its roots stay confined and creates a bushy plant.

Chamaedores costericana...bamboo like palm grows quickly to 8 - 10 feet when well watered. It does well in such large container that you intend. Grows very narrow.

The first thing I thought of when I saw "tall narrow houseplant" is Sansevieria trifasciata. They can take a fair amout of neglect and still survive, plus they should do well in moderate light.

Hey thanks for your advice! Jeannie7, the banana would be too wide unfortunately - the inner door opens into the vestibule with about an 18-20 inch clearance from open door edge to wall/corner. So I figured a 12-14 inch pot won't interfere with the clearance at bottom; and if top of plant stays narrow (max about 16in. diameter, it won't interfere with people either. The ficus might work since I will be able to maintain it; I'll look for the bamboo palm to see how wide they are.

Mentha, yep- I've rcvd. a cut once or twice on some palms - good point I didn't think of! Although the palm (if that's what it is) I am thinking of has very very soft fronds. Sort of reminds me of lily grass in texture, but it sits like a basketball atop a trunk maybe the diameter of a quarter or half dollar and 2-4 ft high. I'm still searching for a photo of one so I'd have a name!

Oklahoma_tim, I will check out the sanseveria - I never heard of it. I thought about having a pothos on a post, but not really sure if that would look full enough. What I really wish I could find is something that would flower like a mandavilla vine, but would work indoors. In winter. In Albany! Severely limits the options, huh! The good thing about the space is that the corner is made of 2 large windows, so I think (hope) the light situation is OK.

Thank you all again! Anything else come to mind, I will happily take your advice. Doing this for my friend as a congrats gift!

I think if you want something that's going to climb something else, you're better off if only one of them is alive: living plants climbing living plants can work, but not often enough that I'd recommend it.

Sansevieria trifasciata is a good choice, so long as the spot isn't cold (there are actually not many indoor plants that would do well in an occasionally-cold spot).

Dizyogotheca elegantissima is sometimes temperamental and is prone to bugs, but it does fit the shape you're looking for.

Rhapis excelsa tolerates cooler temperatures better than most, and is relatively easy-care.

Dracaenas are very easy care, handle low light well, and spread very little: see D. fragrans 'Massangeana,' D. deremensis 'Janet Craig' 'Warneckei,' 'Lemon-Lime,' 'Limelight,' 'Art,' etc.

Yucca elephantipes have sharp leaves and need sun, but the shape is right.

Cereus peruvianus and Euphorbia trigona are also sharp and need sun, but have the right shape.

Hanging plants can sometimes be a good alternative to a tall skinny plant, depending on how quickly you need the space to be filled: Chlorophytum comosum will eventually get long and thick enough to be columnar, and is easy to care for as long as you can flush the soil regularly.

Thanks Mr. Subjunctive! I am thrilled that I have so many specimens to look into! And I continue to be amazed at everyone's knowledge & willingness to share! How soon do I have to start using the scientific names of plants? I'm sorta spoiled on going by their more "common" names!

What about a balfour aralia. I think that is the spelling. It also could be called a cane aralia.

Yes - I did see some different aralias that might work also. thank you!

On the scientific name question: you don't ever really have to. It depends on your tolerance for confusion. There are about seven different houseplants, for example, with the common name "zebra plant." Scientific names are less familiar when you start learning them, but the big advantage is that nobody's going to hear you say Haworthia attenuata and picture Aphelandra squarrosa in their head. Which is good, 'cause they're not very similar in appearance, care, size, or anything else. Except common name.

Also some common names are really regional. Everybody in your neighborhood might know what a (just making up a name off the top of my head here) kangaroo-pouch plant is, but if the person at the store doesn't know it by that name, they won't be able to help you find one or grow one or anything else.

Granted, in a lot of places, I'm not sure that the staff know the scientific names either. But still. It's the principle of the thing. And it's better than standing there trying to describe a plant from memory.

Just wanted to pop in and say that the most common "common" name for Sansevieria is "Snake Plant."

yes - very good stuff to know. I'll probably learn as I go. The internet & this site in particular have been a great source! thanks for all your input.

When one wants to learn botanical names, a good site for help in that is:

desert-tropicals.com

they have things categorized in a very helpful way: BOTH by botanical name & by common name. They also have a pretty good succulents section (where I started learning their names).

I don't like common names because they're, oftentimes, not very inspiring. I think dawn redwood is a very nice sounding and evocative name, but then you get things like Cryptomerias being called Japanese Cedars, which if you ignore the fact that they're not cedars, just doesn't SOUND as nice as cryptomeria. And Japanese Umbrella Pine is a much to mundane sounding name for something as weird as a sciadpitys. And "sago palm" just doesn't sound like a primitive dinosaur plant.