When thinking of a custom installation for a large space, always consider Aqua Creations. Their signature pieces are particularly suited to large spaces -- they understand large spaces. Here is an installation in Valencia, for example:
They have the creative skills (thanks to the inspiration behind Aqua creations, Ayala Serfaty), they have the design and engineering skills (because they develop all their pieces themselves) and they have the skilled artisans to make bespoke lights (because everything they sell is handmade by their own team). But maybe most importantly, they relish the opportunity to work on bespoke installations (an enthusiasm not demonstrated by all producers...), so they set about them in the right frame of mind.
Here is a case in point. The location is an office block in Melbourne (321 Exhibition Street). Aqua creations worked with their local partners ECC Lighting + Furniture (in whose Sydney showrooms, many years ago now, we first saw and were knocked out by, Aqua Creations lights).
You see in the image at the top of this post a Standby incorporated into the basket surround. Here's a clearer image of a Standby:
but a smaller one -- the one in Melbourne is Ø2400mm!
Further along the lobby, Aqua Creations created a square installation for a square basket...
...OK, they're not baskets, but you can see what I mean -- I don't know what else to call them.
They look quite small from a distance!