Has anyone heard of this being done or a business growing out of the efforts?

Yes, I've heard of it being done, mainly by Garden Clubs and mainly for indigenous wildflowers/shrubs, etc., as far as demolition sites are concerned.

And no, I haven't heard of a business being formed to do same, just the dedicated interest of those wanting to preserve certain endangered species.

Carolyn

I know of several people who do that, more out of a sense of responsibility than anything else. None of them does it as a business, but at least one of them (wish I could remember who it was) formed a network of like-minded individuals in her area who now operate as a club.

There used to be a company in, I think, South Carolina that would go ahead of road crews & rescue plants, they then sold them via catalog & the money went to buy wildland & keep it wild. I can't remember their name it's been so long ago.
I'm in the middle of a plant rescue here on the island, my brother lives in a trailer park that is being closed, all the tenants have been evicted, Jan. 31st last day there. I've been digging up crinums, hymenocallis, some iris, aloes, sanservia and other plants left in the landscaping. I just wish I had the ability to dig & move the big orange trees that will soon be bulldozed. If I see a construction site I pull over & ask if I can dig, same thing if there is a house they are tearing down. Most of the time noone cares & sometimes I get the work crew to help! Once they even dug several huge clumps of bananas & put in my truck, I looked like a mobile produce farm going home.
never hesitate to ask, I hate to see plants killed, then replaced with generic boring landscaping that is unsuitable for the area.
Tally HO!

Just an fyi, and not plant related, but there are also groups that go to places that are being excavated and dig for arrowheads and other artifacts before the work crews come and cover everything with concrete and asphalt.