Dirtslinger2...Aside from artificial lighting, are there any windows in the room?

The tallest, low-light plant that comes to mind is Dracaena, 'Janet Craig.'
One problem, aside from light is, 5-6' trees might be hard to find.
Home Depot sells tall Dracaenas every so often, but unless they're newly shipped, more often than not, plants acquire insects. On the other hand, D. Janet Craig, although not infallible, is hardier (insects) than other plants.

There's a Spathiphyllum 'Mona Loa.' Spaths thrive in low light, but do best in medium. I believe ML is the largest of Spahtiplyllums. We used to sell them at Rentokil. The tallest were 4-4.5' tall. They're beautiful plants, look great in an room with a lot of space. White flowers form periodically. Between the size of the plant and flower stalks it'd near 5', but you can't count on blooms.

All plants need light. Will these plants be kept in the same location year round, or can they be taken outside in summer? Toni

Great ideas, thank you. Both would suit it well actually.
They will be in the lobby of a hotel, so additional lighting is unlikely. It is a vaulted ceiling with north facing windows at the ceiling level only. They would not get outdoors at all.

Rhapis excelsa, the parlour palm, is the most tolerant low-light architectural plant I've ever come across and survives the most unsitable berths in gloomy restaurants and offices. It will take a lot of abuse and has the height you want. Very slow growing indeed, and hence expensive to acquire if you want a readymade large specimen. Why not anyway improve the light levels in your chosen spot? Say, a 125 watt compact fluorescent in a downward reflector hung at ceiling height and set on a 12 - 14 hour timer?

I guess the hotel setting rules out adding better plant lighting fixtures (but you could still suggest it, no? Maybe a small and discrete halide lamp such as hotels use all the time in halls and atriums?). From how you describe it, I'd still say Rhapis excelsa will survive in that location anyway - they really do take the 'low light' title! They would need a 'night' period of darkness too though - if the lights are on 24/7 uninterrupted for the benefit of guests that's going to stress any plant.

Steph, Parlor Palm botanical name is Chamaedorea elegans. But Rhapsis excelsa, Lady Palm, does fine, or is said to thrive in shade, too. Toni

Rhapis excelsa tolerates lower light levels than Chamaedora and lower humidity too, so it was the former I was recommending for the tricky hotel berth. I think of both of them (and Kentia) as 'parlour palms' in the generic sense.

I am in hotels more than I am in my home. I stay at Marriotts, and Hiltons. What I have seen more than any other plants is Sanseveria, Dracaena marginata (Tricolor Dracaena), Bromelaids, ZZ Plant.

The sanseveria are in very large tall pots about 4' tall with ivy at the bottom drape down around the plant and hanging over the edge of the pot.

ZZ Plants again with ivy at the bottom

Dracenea were also in tall pots with colorful gravel

Bromelaid - This was very pretty. They have a large tree limb and the bromelaids attached to the limb and small bromelaids as ground cover.

All these plants I have seen in the hallways with no windows on the hotel room floors and in the lobby.

dirtslinger, I just noticed you said they are lobby plants. The reason for the large pots in a hotel lobby is because of people rolling luggage. You do not want a tall plant/tree in a low pot in that area.

Rolling luggage is pulled behind you making it dangerous that a wheel will hit the pot and it is pulled by a luggage wheel toward the hotel guest.

If the hotel is requesting a tree that tall make sure you point out the danger and if you are purchasing the pot be sure you add the weight and type of pot you are going to have to use in that area for safety.

Corporate lobby plants are often leased from specialist contractors who regularly swap them for healthier specimens that have been holidaying in glasshouses between gigs. It's rest-and-recuperation time before they're put back to work. How else do you imagine high-light genera like bromeliads could be surviving in no-light environments?

Steph, you're right. I used to work for a nursery, 'Rentokil Tropical Plants,' (originated in Enland.)
I worked in the outlet store, but we had techs inspect rented or purchased plants in malls, hotels, etc, daily.
Except for super-large trees, grown in-ground, 'indoor malls,' smaller plants were either tended to or replaced.