PS--I'm in Dallas, I think in zone 8a, in case that affects your thoughts. And this area gets pretty full sun, though of course it's by a fence, so for at least part of the day it's in shade when the sun's on the other side. Thanks again! :)

Some say they are over-used, and some say they are invasive, but the most narrow shrub I've ever seen that does well in your situation, with very little maintenance, is nandina. It's evergreen, in full sun the leaves are greens to ambers to reds to pinks. Very light airy foliage and very pretty. The standard nandina can get upward of 8 feet (easily pruned to stay shorter) and it will spread by underground runners. It has small clusters of white with yellow blooms, and makes nice reddish berries for fall thru winter. Gulfstream nandina gets about 4-5 feet tall, but doesn't spread, so would need to be planted fairly close together. No blooms or berries on this one, but still the light airy foliage with new reddish growth. Just about anything else with a decent height will need to be severely pruned to stay narrow. There are many more nandina cultivars, but these are the only ones I have personal experience with. I really love this shrub.

Gosh that's tricky. I'm thinking of my own similar spots in our yard that have full sun. We've got a silverado sage in one tiny area, and I just prune it back once every few years. If you can wire the fence, maybe a lady banks rose. No thorns, evergreen, but you'd have to wrap it onto the wires initially and prune it heavily once a year to keep it from going too wild. Could you do a small tree that leaves head room for the walkway area? A lorapetalum pruned into a tree would work, and you could even prune a variegated privet into a small tree. Argentine Senna... can't remember if that's evergreen but I'm thinking it's not. Nandina is also a good suggestion. If you chop it back once a year, you could put a knock-out rose in that spot. Coralberry might not give you as much height as you want, but it's evergreen and gets gorgeous fuchsia berries. Mine are only in partial sun and are about 3' high. Virginia sweetspire? Not sure if it's evergreen here or not. Seems like it loses leaves at a certain point. Pyracantha? Cotoneaster?

Ok, I sent this link to someone else. I'll send it to you too. I'm dying to try this in my own yard myself.

Here is a link that might be useful: Sky Pencil

Will Fleming yaupon is a very tall, very upright evergreen yaupon. I think it can get wider than 2 feet, but you can prune it. It's like 20 ft. tall and 2 ft. to 4 ft. wide.

Dwarf wax Myrtle is an evergreen native that stays compact on it's own. It says acid soil but I'm growing mine on clay caliche. PJ

Here is a link that might be useful: myrtle

I would try sweet olive (Osmanthus fragrans)
if it doesn't fit there for you, be sure to try it somewhere! I It is very easy to keep trimmed up and still looks good.
Lucy

Thanks for the suggestions, guys. It looks like I have several plants to go look at and learn about over the weekend. Calloway's, here I come! I'll post back here once I've looked into it and made a decision. I really appreciate everyone's input!